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How important is negative pressure?

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#1 madgoose

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Posted 11 October 2020 - 09:02 PM

How important is negative pressure and what does the correct rate of negative pressure achieve?

 

I have recently completed some upgrades to my permanent grow room in the garage which was built in late 2009 and I have only ever grown in it once, and at a time when I did not have a lot of experience. Since then the learning curve has drastically changed and as a result I monitor and watch a lot more parameters which I did not understand the importance of back in the early days. I few months ago I "took in" some cuttings that had to be relocated quickly and quietly so I set up my Secret Jardin Dark Room 2.4 x 1.2 in the dining room to accommodate them while I made the grow room in the garage accessible.

 

I have used the tent in a number of locations at different times of the year and I usually use 3 x 600 watt HIDs which give me a continuous "daytime" temperature of around 31C and a humidity reading of low 40%, using NFT means that I don't usually need a humidifier but I do have a small one on hand. With my current project i am not using NFT but a soil compost manure mix in 400mm(H)x 500mm(Dia) which is 78.5 liter planters.

 

Extraction methods previously and currently employed.

I use an Ecotechnics digital fan controller and have a number of fans, (I will include a screen shot of a spreadsheet with the technical data for the fans that I have at the end).

 

Grow room 2.4m x 1.2m

The first time I used 1 x Air Vent Technology (rated at 389m³/hr) for extraction with a passive intake through a 150mm hole

this time I have set up a 150mm Systemair RVK (rated @ 720m³/hr) for my exhaust with a 150mm x 600mm Rhino carbon filter, which has flexible silencers before and after the fan and a 150mm HVK (rated at 680m³/hr) for my intake, this has a "homemade net curtain filter", a backdraft fitting and a fabricated 90 degree right angle fitting.

 

SJ tent 2.4m x 1.2m:

I have set the tent up in the past (using the same lighting rig on each occasion) using my 150mm Systemair RVK L1 (rated @ 720m³/hr) and the 150 x 600mm Rhino carbon filter with a passive intake,

as above but included the 150mm HVK (rated at 680m³/hr) for intake,

and have also used a 200mm Systemair SileoE2 (rated @ 796m³/hr) with the Systemair 150mm L1 (rated @ 720m³/hr) for intake.

 

These all manage to maintain a temperature of 30-31C and a humidity ranging in the low 40% and very good negative pressure. Except for the current set up in the grow room which is holding the temperature at about 30-31C but with very low humidity, about 20-25%. I have a small humidifier and a bucket full of water in there at the moment and tomorrow I will fill some 0.4x1.2m trays with water and put them on the floor to try and increase the humidity. I know I need some new hardware and i will be doing some shopping for the new kit in the new year so this should rectify the humidity issues.

 

I also seem to have very low negative pressure, which is to be expected seeing as the exhaust is 720 and the intake is 680. I have bought 2 x 200mm-150mm reducers and was planning on changing the 150mm RVK L1 for the 200mm SileoE2 to give a bit more pull. The Rhino 150 x 600 is rated at 900m³/hr so I don't foresee any problems there. But just how important is negative pressure and what problems arise due to a lack of it. I seem to be experiencing "micro climates" around my grow room. With different temperature and humidity sensors throughout the grow room I see different measurements in different places. I have a 230mm desktop fan on the floor oscillating to disperse my incoming air, any warm air if my oil rad kicks in and humidifier then I have 2 400mm pedestal fans at each end. I do have 4 more 300mm box fans which I was planning on adding but if the issue is caused by having the incorrect setting for my negative pressure then I need to increase the size of my exhaust or decrease the size of my intake fan, not throw more oscillating fans at the problem.

 

Here are the copies of the spreadsheets of the available kit (if it is written in blue then it is on the shopping  list) so your thoughts please on any adjustments using what i currently have. Being that the grow room is made of 12mm ply, 25mm battens then 50,, insulation boards I don't really want to be having to take the jigsaw to it especially as it is going to have a major overhaul in the new year tripling the overall grow area. these mods are just for the current grow to get the best out of what I have. The second figure in the column for the "flow rate" is 2/3 of the actual flow rate, two thirds being the advised difference between the exhaust fan and the intake fan to achieve the correct negative pressure.

Attached Files


Edited by madgoose, 11 October 2020 - 09:09 PM.

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#2 NemesisOne

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Posted 12 October 2020 - 12:00 AM

Howdy man, that was a good read and wow, thats some tech you got there, the EcoTechnics Controllers are superb, my favourite. 

so i thought id be polite and put my thoughts in..

 

Right, so, the question,,, if im right in thinking is,

 

"But just how important is negative pressure and what problems arise due to a lack of it."

 

All i know if you havnt got enough negative pressure then the your not pulling everything through the filtration system, the smell will leak out from zips etc... 

and your plants arnt getting enough O2.

Too much,,, well, have you sat inside a tent and put it at max, sealed it all so it really sucks in? 

 

Have a go if you havnt as I have and its friggin weird,,lol,, you can feel the pressure, a few of us tried it with a over kill setup, ie,10 inch extraction fan in a 1.2 x 1.2 tent... 

lol. we were going to try to implode it. to test the strength of the poles,, but,,, alas, it was saved for a vegging tent... boooooo. 

 

Anyway, it can freak your ladies out,, in different ways, it can affect the RH and temps aswell, cause hotspots etc..pressure is a weird thing.

Im sure someone with a lot more experience with that sort of thang  will also pop in. 

Apologies for not helping more, I normally use stealth cabs you see? solid walls, no sucking in or out, so my experience in this field is a bit lacking. 

 

 

 


Edited by NemesisOne, 12 October 2020 - 12:02 AM.

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#3 madgoose

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Posted 12 October 2020 - 03:21 AM

Howdy man, that was a good read and wow, thats some tech you got there, the EcoTechnics Controllers are superb, my favourite. 

so i thought id be polite and put my thoughts in..

 

Right, so, the question,,, if im right in thinking is,

 

"But just how important is negative pressure and what problems arise due to a lack of it."

 

 

Thanks for responding fella, much appreciated. I was lucky, when I first started I bought a parcel of used equipment, then with 10 years of upgrades and changes I have gathered up quite a bit of kit, especially as I normally have a veg tent and a flower tent running at the same time. Yes I have sat inside a tent with negative pressure (messes with your ears and eyes a bit) and I had my 2.4 x 1.2 tent collapse due to the middle poles giving way because of the negative pressure. When I use the 150mm L1 for extraction and the 150mm HVK (same as an RVK just different manufacturer) the fabric of the tent becomes as tight as a drum and I lose about 100mm-125mm on all sides. The 150L1 changes the air in that area 36 times an hour instead of the required 20, I use it due to running an additional 600 watt HID on top of the recommended 2. To help combat this and give the framework some additional rigidity I bought some utility shelves which comprise of 5 poles, 4 of which which fit into plastic fittings that sit on the poles and screw tight at the required height and the fifth runs across the width supporting the weight of the metal grill shelves that create a scrogging effect. The shelves are designed for a 1.2x1.2 so I use 2 in the 2.4x1.2.

 

In this instance I have relative uniform temperatures in the tent, the problem is in my permanent grow room which is extremely stealthy, I know this because I was worried about being discovered through thermal imaging cameras to the point that i considered hiring a thermal imaging camera and chartering a helicopter to check for myself. However before I could do this it snowed in late December 2009 (the only time I have used my permanent (stealth) room up until now) and getting up on the garage roof expecting to find a patch 2.4x1.2m where the snow had melted it had not and 10 days later the snow had melted everywhere else on the garage roof EXCEPT for immediately  above the grow room and it took another 4 days before the snow had melted above the grow room and the garage roof was totally clear. When I recover the data from a partially reformatted (by accident) hard drive and can access the photos of the build I plan to start a thread detailing how and what I built and the materials used. Basically 12mm ply and 50mm Celotex/Kingspan insulation boards with some other goodies, I think people are starting to realise that i am into overkill (especially for safety and security).

 

The problem that I am trying to address today is what I described as "micro-climates" (for want of a better phrase) but what you have correctly called hot spots. In the permanent/stealth grow room my Ecotechnics is reading about 30-31 at the top of the canopy. I know this because I have a number of digital and analogue temperature and humidity monitors on a polystyrene box at the same height as the Ecotechnics sensor. All are +/-5% so i work with the average measurement. When I put the additional monitors on the floor I am getting about 28C and similar humidity levels but i have a shelf at the back of the grow room where I put my additional monitors the first night of operations and was getting readings of 42C but the Ecotechnics in the middle of the grow room was reading 32C. I thought they must be out of calibration (having experienced 44C and 10% humidity when I lived in Australia)  because it did not feel like 42C in there when I entered and closed the door. I moved the Ecotechnics sensor to between the 2 monitors on the shelf, closed the door and walked away for an hour. When I came back to check up on things the Ecotechnics was also reading 42C so i definitely have hot spots. I feel I have sufficient oscillating fans but over the next few days I will be relocating them and using them in different combinations. I usually find the 300mm box fans are best, i can tie them to a EZ roller, position them at the required height and they only need to be a few mm from the wall to operate efficiently and are the same size as a record album and only about 60mm thick.

 

So do you think that the hot spots are due to bad negative pressure or bad air movement because of the oscillating fans being in the wrong places or wrong heights?

I did not mention it before but the first time I used the grow room when I used the 150mm Air Vent Technology cage fan (rated @ 389m³/hr) and a passive intake I did not have a door handle only a screw in the door and I had to get a pair of pliers on it to wrench the door open, at the moment i have no issues holding the screw between my thumb and index finger to open the door, which is how i know that the negative pressure is low. Before I start changing and relocating the oscillating fans I guess I should unplug the intake fan as this would mimic the previous passive intake and should give me double the negative pressure I had in that grow room on the first occasion and then i can monitor for a change in the hot spots. If that fails I guess I am going to have to run 10 meters of 150mm flexible ducting under the garage roof and through to the loft of the house like I did the first time, I guess I should not a little bit of awkward hard sweaty work swimming around in insulation rock wool put me off! I'll probably be doing a thread around the end of March next year on "How to build a closed system room and install and use an Opti-Climate air conditioning unit"!


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#4 NemesisOne

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Posted 12 October 2020 - 12:45 PM

Hi mate, my absolute pleasure, if someone goes to the time to write such a detailed post like that then i felt that a response is needed, even if it was a small one.

 

Firstly, this will confuddle ya, i dont use intake fans and never have. Grown all over the world, Holland, spain, america, canada & still didnt use intake fans.

Even my mate TeeTee in Australia, doesnt use them either and hes in the outback, very hot and dry...and full of snakes, lizards and spiders,,, feck that. lol 

 

Reason? they feck up your temps, they raise them in summer and lower them in winter,,, plus all that balancing act between extraction rates matching the intake rates.?

nah mate, i just use passive intakes and speed control my fans,, not with a EcoTech tho,,, had one once in a big tent, now ive gone smaller, not really much need for it

so i donated it.

And my opinion about your funny temps etc.. try turning off your intakes or remove them and see.

might not make any difference but you never know..its always the simplest things.. overthinking can add more to the problem then solve it.

 

I run 6 inch fans normally, half speed, still get a bit of negative pressure as no smells,, plus if i put my hand in my intake hole you can feel the air rushing in..

so why push it?

I do use LEDs tho, temps are a lot more controllable,. everything is lot more controllable in fact. Hence i changed over years ago.

 

Bottom line, temps dont really bother me either, i was rocking at 39 - 41 C a few times when i was journalising in a 240 x 120 x 220 high GreenQube tent

hot wasnt the word, i really tested my leds for heat failures as well as they were hitting 50C lol,  and they handled it.

Even more strange, the ladies inside loved it... which made me think that some strains like the extreme heat as thats where they originally come from.

Now with high heat tho comes Humidity problems, jungle jim mate. sweaty betty, thats what it was like going in there,,, apocolpyse now heat. lol.

 

Best way to deal with that is, as you state, fans,, to mix all the layers of hot and cold up as cold air is denser & will sit at the bottom, so you have to push it upwards

I have a litte 6 inch fan on the floor, right by the intake, aiming upwards,,, now this is a sort of intake fan but its not directly connected to the ducting.

so the tent can still 'breathe', ie, suck in more air if it needs to, not forced to.

 

Now i could be babbling here as ive been up all night running 250L of water through all my ladies ready to come down, had mass amounts of smokage and coffee

and have just had a mind numbing bubba kush reefer, packed full of degraded THC. lol. coma weed mate, so im slowly going into the world of Alice....

 

but,,, {snapping back to realaity}

its another option to try eh? keep all the fans as they are, turn off or remove the intake and put some fans on the floor helping the cold air mix from bottom up.

 

A good way to test the strength of the passive intake is too leave the intake fan in the ducting, but switched off, if good, the fan will turn itself. saves leccy. lol.

 

Now, anoher thing caught my eye, thermal imaging from copper choppers? .... yeah heard it a billion times, if your seeing choppers floating about doing circles in the sky

and its got a little red dot on it, underneath, then that is a thermal imaging camera,,, but not what you think... its not the coppers buddy, its more likely the 

Electric board,. they take survey shots at night with them. Pics up the power lines easier. 

How do i know this? i know pilots mate, RAF and Normal. Sure they do work for the coppers,. chasing cars and idiots running away in woods normally.

Not growers roofs. lol,,,, nah the powers to be usually rely on other methods of stupidity, smell being the main one. neighbours grassing... etc.

the grower being a loud idiot being the second. lol. 

One of the guys i know is a grower himself, his wife has MS... so there you go,,, main point is, dont rock the boat & 'they' wont rock yours.

its people who take the piss they slam.

 

The snow on the roof melting is a good sign tho. lolol. even in holland that is laughed at & checked, as there you have to inform the authorities 

and your landlord {if you rent} that your growing, you then pay tax... as if you dont & you grow and get caught by a melted roof {as they are on it over there}

they will actually prosecute your landlord as well as you. lol. 

they dont give a shite who bleats what in their defence,, money  talks and it talks fast. Same in Thailand. lol eep dont go there tho.

Laos is the place to be. lol they deliver it to your door. Like lets eat.... or lets smoke rather...

 

so, that made me laugh, ive seen plenty of roads in the uk like aswell in winter when im over visiting family and the like. lol. does make me chuckle the fools.

asking for it. comes to mind.

 

lastly,,,blimey, a closed loop system eh? now that is the top grow room to have. Seen setups of those at shows with leds etc.., science fiction at its best.

recirculating o2 etc, Ozone scrubbers... yeah man that is the nuts and what Mars One are using when they live on it. Google them.

 

Thinking about it, your garage,,, and all that tech you have? why dont you scrap the tent mate, make the garage the tent. No neg. pressure then eh?

i know plenty of people who did it. built frames etc.. and with your skills and knowledge?,, NASA might even have a look in. lol.

 

well hope that wasnt too much of a babble,, Mr Bubba is wearing off slightly now so time to refresh and refill this old coffee cup

this old git aint crashing out yet, i can keep up with the best of them........y awwwwwwwn. lol. 


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#5 madgoose

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Posted 12 October 2020 - 03:09 PM

Hi mate, my absolute pleasure, if someone goes to the time to write such a detailed post like that then i felt that a response is needed, even if it was a small one.

 

 

Thanks for taking the time, you covered a lot and have confirmed some of the methods I considered for my process of elimination. In regards to my detailed post if i can write something that I have learnt through either research or experience and somebody else can benefit then I am all for that. I totally detest "text" conversations "ya get mi blud" and threads were people ask a question, get a few answer and then never return to their own thread, so you do not get any feed back if you are watching the topic yourself, 2 way street and all that, the knowledge is in the details don't be scared to read a book. What did Chris Rock say? "Hide the money in the books".

 

First, I only use tents when I am "on tour" or in rented accommodation. Second back in 2009 less was known about the methods that "they" used and there were rumours all over the internet, grow shop backroom chats about the thermal imaging that was available to "them", I ended up finding the website of the manufacturer who sold the cameras to "them" and they are more than capable but the reality is unless they have an inclination through other intelligence "they" ARE NOT PAYING OUT £1000s per hour to do some Inspector Clueso work in their chopper. I sat in a flat in North London for 5 years using my tents above some shops which had absolutely no insulation on the ceiling or the slate roof. I had a 1000watt air cooled with a 150mm RVK in my 1.2 x1.2 with 100mm RVK for  extraction, then a 200mm RVK extracting from my 2.4 x 1.2 and the pair of 150mm air vent techs, one at the beginning pushing and one at the other end pulling through a chain of 3 600 watt HIDs air cooled. All this was going straight out of the plasterboard ceiling into the loft cavity and hitting the slate roof 3 m above them, continuously day in day out for 4.5 years. Previously i had lived in a loft conversion 2 doors away and for 10 months as I lay on my bed I watched a helicopter flying a grid pattern over London through the Veelux window, so i feel the allegations regarding the whirly birds are an absolute myth like you said if you rock the boat then they may well ask the crew to have a peak at you when "they" are in that area on a quiet occasion, but they are not out there randomly searching, however they now have drones that are equipped with TICs and are lot cheaper and easier to chuck up and do a quick aerial survey.

 

Through process of elimination I was planning to turn off the intake fan for 24 hours and monitor the results as my next courses of action. I feel it will definitely increase the negative pressure and this hopefully should resolve the issue with my hot spots. I can then fine tune it using the min/max fan setting on the Ecotechnics if it suffices if not rig up the 200mm and see if I can achieve the desired results with that in place.

 

I have completed grows in the middle of summer hitting 35C every night (lights on) using NFT before I had a chiller and still achieved my expected average yields with no issues but nutrients slightly more diluted than usual and the delivery pump on for the duration of the lights on cycle. We switched over to the air-cooled rig one night to try and get the temps down and ended up working in our boxer shorts trying hard not to get out noses to close to each other arm pits so I feel you on the JJ & SBs. LOL!

 

Regarding what you said about certain strains thriving in the heat takes me back to something I read years ago about CO2 levels and plants. The strains we are working with are max 40-45 years old and that's if your working with a Skunk#1, Northern lights, Silver Haze or something similar,  most are a lot younger. People say that these strains have been developed and modified for hydro/artificial/forced gardening but the reality is that they are just a careful selection of phenotypes cross bred to produce similar consistent characters to marketed under the licence of a brand, the reality is that ALL of these share genetics that are probably tens of millions of years old. Going back to the CO2 mention, we currently have an average CO2 content in rural areas of about 400 and in urban areas 600 parts per million, but plants can digest up to 1500ppm because many many years ago there was a lot more CO2 in the atmosphere and the genetics of the plants are still wired to deal with those parameters. If you are new to CO2 be careful, it is like turbo charging your garden unless you have everything dialled in correctly you will just create problems for yourself a lot quicker, yes plants are supposed to be able to take considerably more heat in fact you are supposed to bring your temps up to mid 30sC when you are using CO2 but you also have to dilute your nutrients accordingly and adjust your humidity, get this right and you will increase yields and reduce your flower cycle time but there are other ways of doing this as well. <<<Sorry didn't meant to preach just sharing.

 

The reason I am considering a closed loop with the opticlimate is because i have been offered 9 x 1000 watt Dimlux Expert Series and i have a real liking for the Dimlux control unit, as well as having the now regular features of total control of manual dimming, auto dimming to maintain temperatures, sun rise and sunset features it also has an asynchronous setting which gives you the ability to create a 24 hour period (for the plant) in 20 real hours (10 hours lights on 10 hours lights off) which means the plant sees a full 7 day week in 5.83 days, a week is a 168 hours but the plant register the week in 140 hours, saving you 28 hours per week meaning that you should be able to reduce a ten week flowering period (which is what I usually do on most strains) in 8.33 weeks. Also the Opti-Climate plugs straight into the Dimlux controller. This in a 3.6 x 2.4 will need the A/C, I am considering the water cooled rather than the air cooled and am planning a closed loop for the water, I am just working on how to cool the water to re-use it. I cannot afford for it simply to go down the drain as I am on a water meter and it uses 5+liters per minute. Maybe build a pond in the garden and run a pipe around that a few times or run the hot water pipes under my outside raised beds for my veg (tomatoes, chllies, potatoes, melons, spinach, lettuce, okra, etc). Couple this up with a 9 site Alien RDWC with chillers and i think i am ready to put my 10 year learning curve to the test. More light, more square meters less plants is the theory. I know i could get 4 times that comfortably in that area and under that lighting rig but i have achieved the same yield form 40 cuttings as I have from 9 cutting in the exact same set up and location. Obviously if you lose one out of nine it is going to affect your final yield a lot more than if you lose 1 out of 40 but if the door goes in and you have 40...

 

I have been out of the loop for a few years and in that time I have not followed the latest trends and advances in technology but i can see that LEDs have come a long way, some of my younger friends tell my that i am still growing analogue and everybody else has gone digital! My attention was bought to Spider Farmer LEDs and I looked on the usual forums and saw a lot of skepticism over a Chinese product that was being marketed in a different format even though it claimed top quality components and local distribution. Until recently i had not spoken with anybody who had used them nor had i seen them. Then a new face started working in my local grow shop who had experience with them and had bought the SF1000 that he used to use as a demo in the shop, I was impressed but not ready or able to spend 6 x £600 for 6 SF4000s. Because of the skepticism and the fact that you cannot connect the Spider Farmers to a lighting control unit other than a timer (the new ones are manually dimmable now) I continued looking into LEDs and felt that the new Lumatek Zeus 1000w Pro LEDs will probably be the direction I move in because they are compatible with the Dimlux light controller and should be on the market by the time I am ready to make a purchase.

 

Definitely not a babble it's good to share and exchange views I just hope I don't come across as a "Billy Big balls" it is just that these are the opportunities that have been presented to me and sometimes you have to grab the bull by the horns. I hope people feel easy to comment and contribute I don't intend to be gunning anybody and if i can help feel free to ask me, I definitely do NOT know everything so i am open to suggestions and advice, but i don't like dicks. The permanent structure is definitely the way forward and will be up scaled after a couple of small grows in it's current format. I may still use a small tent for veg/cuttings and mums or may build an annex onto what is the main flower room which will also give me the benefit of being able to recycle my hot exhaust to the other area to keep my "night time" temperatures up and reduce the power consumption a bit.

 

Final comment: Does anybody have any experience with the Solar Cure UVB systems @ 288nm and the UVR8 protein that they mention? Apart from the obvious benefits that they mention on their website and the fact that they claim it can keep spider mites and other pests, moulds and mildew at bay i am curious to see the results it could have on my fig and avocado trees that i started off in the tent when it was on veg cycle with metal halides back in March-April and then when i took them outside when the weather improved in June all the new foliage shriveled up like they had been burnt.


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#6 NemesisOne

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Posted 12 October 2020 - 05:20 PM

yowza mate, oh your not preaching or billy, its certainly not taken that way, im just blown away with your tech knowledge, you got more gear then a grow shop lol. 

Its quite obvious its a real passion mate, hats off to you, getting to your level of expertise isnt just by reading manuals eh? lots...years..of practial experimenting...

does surprise me a little that your scope of leds is just down to those tho,,, spider and the lumi,, dont really like spids, but the new lumatek looks funky.

Symbol22's got that on on the go now hasnt he?

 

Well leds are the way forward, like it or lump it, theyve been threatening to ban high pressure ones for years,, and its now kicking in, replacing street lamps etc..

even tho they do look shite. too bright,, not the orangey glow we all grew up with, but theyre working on that as people are moaning to their mps about it.

but each to their own & you cant argue with the results you get from them types of HPS.. whatever.. grow bulbs,, theyre just not very good for the planet.

or others for that fact. lol. 

 

It wasnt just about the new tech of leds either, it was a new way of growing to be learnt.. so lots of bad press from experienced HPS growers,.

if it aint broke, why fix it.. so they stay with what they know and respect to them rather then risk a shed load of money just to get 

little results..

i think leds were more for the 'little cab in their bedroom' growers to be honest, not the big players. 

My younger brother grew one in a cardboard box when he was at uni, got 2.5 oz from it, dry, so was happy.

There would be no way he could use a HPS, so all about the need.

 

lol@ do not like dicks,,, yeah i got that rep aswell my friend.. much to the annoyance of some. suck eggs is what i say.

but i aint here to piss on anyones fire & bleat its raining... im here for a good read and to injest some of the new tech and knowledge

and to help, even tho my knowledge is a bit prehistoric,,, lol, especially after reading your posts about all that tech.. love it.

 

and at least i was the first 'brave' one to go in first and reply to a genius as yourself, with no fear of 'dicking' myself...

as 'who dares wins' eh brother? lol

 

lastly, UVB systems? wow. nope, all i know about that is UVB is deadly aint it? causes loads of damage, or is that the other one?

either way, if i cant see it and it hurts me, that scares the jizz out of me man so i dont go near UV of any kind.

Early russian astronauts certainly have proof of that... jeeees. frazzled mate. poor guys. 

So be safe yeah? lol i got a feeling you know what your doing tho so this is going to be a interesting read if your also getting into that aswell.

Cool, literally. lol

 

p.s. dangit, i thought i got it perfect first time, nope, edit edit edit... lol

 

PeAce

 

 


Edited by NemesisOne, 12 October 2020 - 05:24 PM.

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#7 Anonymiss

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Posted 12 October 2020 - 06:11 PM

But just how important is negative pressure and what problems arise due to a lack of it.

 
As mentioned above, it's really only about making sure there are no leaks - As long as all the air exits through the exhaust fan then it's all good :)
 

I seem to be experiencing "micro climates" around my grow room.

 
I've found that introducing the air part-way up the space and then extracting from both top and bottom helped with that, and did away with the need for an oscillating fan.

post-7-0-89837500-1530988473.jpg

Things have evolved a bit since the photo was taken and the inlets are now at different heights to each other and they have flat -> round adapters and PSU fans on them, and those fans provide enough turbulence to ruffle the leaves and move things about a bit without it getting too windy or buffeting the plants around.

 

There's a bit of a discussion on top vs. bottom extraction here: https://www.t-g-c.nl...t-from-the-top/


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#8 symbol 22

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Posted 12 October 2020 - 07:39 PM

Brilliant this !!! Really interesting!!... I'm on the same page as annoymiss with regards to inlet and outlet although I do still use oscillating fan.. Just when you think you know something !!!! Then you fecking high flyers come and take it to the next level.. I feel stupid in here !! I'm off lol
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#9 madgoose

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Posted 13 October 2020 - 01:31 AM

Thank you all for your responses, Anonymiss and symbol 22  it is appreciated I will have to take some time to look into your methods, NemesisOne you already know what it is. By no way do I consider myself a high flyer, genius or guru I am learning and experimenting all the time but once you have a grasp and understanding of the basics it is easier to diversify and feel that you can understand what you are doing to see if you have any negative or beneficial results. I try to make things as easy and simple for myself as possible and this is usually achieved through organisation, whether that is data, storage of hardware, magazines that I read and collect or bookmarks for web pages in my browser, so that i can find my way back to things quickly and easily. I swear by this book "Marijuana Horticulture the Indoor/Outdoor Medical Grower's Bible" by Jorge Cervantes My current copy i have had since mid 2009 and whenever a friend starts to show an interest in growing I buy them a copy. I do this because i know the questions are going to come and I don't mind sharing the knowledge but i like for them to have an understanding first, this way they can read the book then we can have a chat and make sure that they have understood it for what it is. I don't know how many times I have read my copy now but it is always on my desk when I have a project up and running. I read the chapter for what I will be doing next week now and then refer back to that chapter throughout that week whilst I am reading up on the chapter for the next phase of the project. I find it is well written in an easy format that most people can take in and digest. Then when my friends call asking about a matter I can refer them to a page or chapter for them to read and then get back to me and we can discuss. I find this saves a lot of confusion and time as well as helping them to do their own research which benefits all of us because you never know what the next guy will uncover and bring back to the table.

 

Going back to organisation you may have noticed the screenshots of the spreadsheets, these were first designed to help me work out the watts and amps that each system may require so I can install the correct safely rated electrical circuit. It is quick and easy for me to work out the total amount of power that could be drawn and saves me having to search through boxes of kit with a torch and a notepad. There is more on the spreadsheets than just the extraction fans, it has everything on it from my ballasts to contactors, air pumps and water pumps. Once designed updating is just a case of making new entries when you purchase new equipment.

 

Knowledge, reading is the key. When a friend and i first "had a go" in 1995 there was no internet and we spent about £200 just on books so we could research our new subject. We trawled through those books extracting everything we needed to learn to cover the basics. We then had to go out and buy the equipment, it was not like how it is today, there were no grow shops as such but we did find a guy local to us that was selling homemade/semi-professional equipment out of a squat in South London, you could not buy a built contactor but he could sell you the components to build yourself one which is what we had to do. I still have and use one of his 400 watt metal halide systems - with the original Phillips 400 watt bulb! Whenever i go to my local growshop I pick up all the promotions literature for the things that interest me, the free magazines taking time to read them and then keep them on a bookshelf. Urban Garden Magazine is/was great (is it still published?) as is Garden Culture, they may not be specific to what we do but the methods, principles and theories are the same. I am always online researching something relevant. If I need to buy a new TV once i have found a make and model that I like I go online and research it, read the reviews of people who have bought and lived with the product, then when I feel I have made an informed decision I may or may not buy the product, I apply this to every aspect of my life whether it is a car, TV, kettle or a new product for a project, I ain't rich and I don't want to be buying something 2 or 3 times before I "come across" the right product.

 

When I bought that parcel of used kit many years ago (2009) there was a Cannatronics air-cooled lighting rig which had the ignitors built into the shades and the ballasts (i have 2, one 600watt and a dual 600watt) are magnetic with built in Grasslin timers and contactors so you can just plug them straight into the wall. It is quite an adaptable system, you can remove the glass so it does not have to be air cooled and the ballasts run metal halides, hps and dual spectrums bulbs with no issues, these are what i have hanging up in the grow room now. In late 2011 I wanted to run a 1000 watt air cooled system for flowering in my 1.2 x 1.2 so i bought the Lumatek 1000watt Digital dimmable ballast with a 150mm magnum air cooled shade which did the job brilliantly. i usually run metal halides for the first 2 weeks of 12/12 to prevent stretch. This system allows me to dial down the power for new cuttings then gradually lower the light and gradually increase the power, i can actually have this hood sat right on top of the canopy without burning the buds. This is why i did not rush to buy LEDs because when I last needed to buy lighting what was available was getting horrendous reviews, if i had of invested into them it would only of been for the veg cycle. But i can no longer ignore LEDs they are definitely viable now, prices are coming down all the time, quality is going up as are the product reviews. You cannot ignore that they run cooler and use less power both are positive to our needs. It is just a matter of buying what is correct for you, which is why i feel the Lumatek Zeus with a mixture of Dimlux HIDs run on that Dimlux control unit is the way I want to go. I have looked at the Gavita but £1700 is to rich for me. Somewhere recently i stumbled on a guy who builds LED boards for growing and i would be interested in having a couple of custom LEDs boards made just with a far, far far and infra red output to apply to the plants for the last 15-30 minutes of each daylight cycle. Having heard Professor Harley Smith talk on a videoed lecture on youtube he stated that his studies have proved that by giving plants the additional far, far far and infra red before the lights go of settles them into the dark period within 30 minutes of the lights going off otherwise it would take them 2.5 hours to settle in, this means that you can benefit by 2 hours every dark cycle, which is when/how the sugars are produced that give the plants the energy to create the buds. I'll will post the link for the video at the end of the post.

 

NemesisOne I went out to the garage at 16:00hrs, this is usually when my lights fire up for the veg room/cycle but are currently on for 24 hours just to kick start things in the new area after a week I will reduce them to 18/6 and then after another week i may experiment with something I have recently read about (may have been from here) called the Gas Lantern Method "GLM" which is a veg cycle of 12 hours on 5.5 off an hour on then another 5.5 off before resuming 12 hours on and repeating. I hadn't heard of it until a couple of weeks ago but it makes sense to me because it disrupts the rising sugar levels in the plant and lowers your power consumption. Anyway I went out to check on things and had a temperature reading of 35C. So i thought OK new 24 hour period let me reset all of my min/max readings and unplug the intake fan and see what happens. Whilst i was there I had a quick tidy up (regular cleaning is a MUST even if it is just picking up a few dead leaves), and decided to take a couple of photos to show you guys what i have been trying to describe. OK cool, i go inside for a couple of hours and then go back out to have a quick observation a "shuttlecocks" if the temperature had not risen to 39.5. I'm there scratching my head thinking "oh it's one of those days, the test is on", I opened the door to read my temps on the monitors and had forgotten to unhook the temperature probe from the hook on the ceiling that I had hung it on so that it did not get wet or damaged when I cleaned up!!!

 

UV I believe does have some danger to it. I believe it can cause skin cancer if you are exposed to it for prolonged periods of time. When i was out in Australia skin cancer was prevalent amongst the older generations because they did not have the knowledge to be aware of the damage that the exposure to the sun could do to them, there were walk in skin cancer clinics on all the High Streets offering day surgery for the removal of cancerous growths, things are really messed up down there because they are seeing first hand the results of the depletion of the ozone layer which is what protects us from the UV at high levels! I don't know if it is allowed (I guess somebody will let me know if i am breaking the rules) but i will post the link to the SolaCure site from what I have read you use one 4 ft tube per 600 watt light and for a maximum of 4 hours (which has to be built up to this gradually). You can run them for 4 hours continuously or short bursts of 15 minutes with breaks between but for a total of 4 hours on per 12 hour daylight session.

 

https://www.solacure.com/uvr8.html

I like the way Harley Smith presents his lectures he seems down to earth and explains things in a way everybody can understand without intimidating them Harley Smith Class - How To Maximize Your Yields

https://www.youtube....IssZ0Eo&t=2987s

 

 

 


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#10 symbol 22

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Posted 13 October 2020 - 06:14 AM

Thank you all for your responses, Anonymiss and symbol 22 it is appreciated I will have to take some time to look into your methods, NemesisOne you already know what it is. By no way do I consider myself a high flyer, genius or guru I am learning and experimenting all the time but once you have a grasp and understanding of the basics it is easier to diversify and feel that you can understand what you are doing to see if you have any negative or beneficial results. I try to make things as easy and simple for myself as possible and this is usually achieved through organisation, whether that is data, storage of hardware, magazines that I read and collect or bookmarks for web pages in my browser, so that i can find my way back to things quickly and easily. I swear by this book "Marijuana Horticulture the Indoor/Outdoor Medical Grower's Bible" by Jorge Cervantes My current copy i have had since mid 2009 and whenever a friend starts to show an interest in growing I buy them a copy. I do this because i know the questions are going to come and I don't mind sharing the knowledge but i like for them to have an understanding first, this way they can read the book then we can have a chat and make sure that they have understood it for what it is. I don't know how many times I have read my copy now but it is always on my desk when I have a project up and running. I read the chapter for what I will be doing next week now and then refer back to that chapter throughout that week whilst I am reading up on the chapter for the next phase of the project. I find it is well written in an easy format that most people can take in and digest. Then when my friends call asking about a matter I can refer them to a page or chapter for them to read and then get back to me and we can discuss. I find this saves a lot of confusion and time as well as helping them to do their own research which benefits all of us because you never know what the next guy will uncover and bring back to the table.

Going back to organisation you may have noticed the screenshots of the spreadsheets, these were first designed to help me work out the watts and amps that each system may require so I can install the correct safely rated electrical circuit. It is quick and easy for me to work out the total amount of power that could be drawn and saves me having to search through boxes of kit with a torch and a notepad. There is more on the spreadsheets than just the extraction fans, it has everything on it from my ballasts to contactors, air pumps and water pumps. Once designed updating is just a case of making new entries when you purchase new equipment.

Knowledge, reading is the key. When a friend and i first "had a go" in 1995 there was no internet and we spent about £200 just on books so we could research our new subject. We trawled through those books extracting everything we needed to learn to cover the basics. We then had to go out and buy the equipment, it was not like how it is today, there were no grow shops as such but we did find a guy local to us that was selling homemade/semi-professional equipment out of a squat in South London, you could not buy a built contactor but he could sell you the components to build yourself one which is what we had to do. I still have and use one of his 400 watt metal halide systems - with the original Phillips 400 watt bulb! Whenever i go to my local growshop I pick up all the promotions literature for the things that interest me, the free magazines taking time to read them and then keep them on a bookshelf. Urban Garden Magazine is/was great (is it still published?) as is Garden Culture, they may not be specific to what we do but the methods, principles and theories are the same. I am always online researching something relevant. If I need to buy a new TV once i have found a make and model that I like I go online and research it, read the reviews of people who have bought and lived with the product, then when I feel I have made an informed decision I may or may not buy the product, I apply this to every aspect of my life whether it is a car, TV, kettle or a new product for a project, I ain't rich and I don't want to be buying something 2 or 3 times before I "come across" the right product.

When I bought that parcel of used kit many years ago (2009) there was a Cannatronics air-cooled lighting rig which had the ignitors built into the shades and the ballasts (i have 2, one 600watt and a dual 600watt) are magnetic with built in Grasslin timers and contactors so you can just plug them straight into the wall. It is quite an adaptable system, you can remove the glass so it does not have to be air cooled and the ballasts run metal halides, hps and dual spectrums bulbs with no issues, these are what i have hanging up in the grow room now. In late 2011 I wanted to run a 1000 watt air cooled system for flowering in my 1.2 x 1.2 so i bought the Lumatek 1000watt Digital dimmable ballast with a 150mm magnum air cooled shade which did the job brilliantly. i usually run metal halides for the first 2 weeks of 12/12 to prevent stretch. This system allows me to dial down the power for new cuttings then gradually lower the light and gradually increase the power, i can actually have this hood sat right on top of the canopy without burning the buds. This is why i did not rush to buy LEDs because when I last needed to buy lighting what was available was getting horrendous reviews, if i had of invested into them it would only of been for the veg cycle. But i can no longer ignore LEDs they are definitely viable now, prices are coming down all the time, quality is going up as are the product reviews. You cannot ignore that they run cooler and use less power both are positive to our needs. It is just a matter of buying what is correct for you, which is why i feel the Lumatek Zeus with a mixture of Dimlux HIDs run on that Dimlux control unit is the way I want to go. I have looked at the Gavita but £1700 is to rich for me. Somewhere recently i stumbled on a guy who builds LED boards for growing and i would be interested in having a couple of custom LEDs boards made just with a far, far far and infra red output to apply to the plants for the last 15-30 minutes of each daylight cycle. Having heard Professor Harley Smith talk on a videoed lecture on youtube he stated that his studies have proved that by giving plants the additional far, far far and infra red before the lights go of settles them into the dark period within 30 minutes of the lights going off otherwise it would take them 2.5 hours to settle in, this means that you can benefit by 2 hours every dark cycle, which is when/how the sugars are produced that give the plants the energy to create the buds. I'll will post the link for the video at the end of the post.

NemesisOne I went out to the garage at 16:00hrs, this is usually when my lights fire up for the veg room/cycle but are currently on for 24 hours just to kick start things in the new area after a week I will reduce them to 18/6 and then after another week i may experiment with something I have recently read about (may have been from here) called the Gas Lantern Method "GLM" which is a veg cycle of 12 hours on 5.5 off an hour on then another 5.5 off before resuming 12 hours on and repeating. I hadn't heard of it until a couple of weeks ago but it makes sense to me because it disrupts the rising sugar levels in the plant and lowers your power consumption. Anyway I went out to check on things and had a temperature reading of 35C. So i thought OK new 24 hour period let me reset all of my min/max readings and unplug the intake fan and see what happens. Whilst i was there I had a quick tidy up (regular cleaning is a MUST even if it is just picking up a few dead leaves), and decided to take a couple of photos to show you guys what i have been trying to describe. OK cool, i go inside for a couple of hours and then go back out to have a quick observation a "shuttlecocks" if the temperature had not risen to 39.5. I'm there scratching my head thinking "oh it's one of those days, the test is on", I opened the door to read my temps on the monitors and had forgotten to unhook the temperature probe from the hook on the ceiling that I had hung it on so that it did not get wet or damaged when I cleaned up!!!

UV I believe does have some danger to it. I believe it can cause skin cancer if you are exposed to it for prolonged periods of time. When i was out in Australia skin cancer was prevalent amongst the older generations because they did not have the knowledge to be aware of the damage that the exposure to the sun could do to them, there were walk in skin cancer clinics on all the High Streets offering day surgery for the removal of cancerous growths, things are really messed up down there because they are seeing first hand the results of the depletion of the ozone layer which is what protects us from the UV at high levels! I don't know if it is allowed (I guess somebody will let me know if i am breaking the rules) but i will post the link to the SolaCure site from what I have read you use one 4 ft tube per 600 watt light and for a maximum of 4 hours (which has to be built up to this gradually). You can run them for 4 hours continuously or short bursts of 15 minutes with breaks between but for a total of 4 hours on per 12 hour daylight session.

https://www.solacure.com/uvr8.html I like the way Harley Smith presents his lectures he seems down to earth and explains things in a way everybody can understand without intimidating them Harley Smith Class - How To Maximize Your Yields
https://www.youtube....IssZ0Eo&t=2987s


With regards to your custom built led .. Try giving @Forest a shout he makes em. Could be worth your while!!

Reading I have a collection of good literature also brother and its been helpful to me thus far!!
Attached File  IMG_20201012_145334.jpg   177.64KB   0 downloads

And lights I also looked at the gavita !!! There is a saying ... You get what you pay for (research research research that's the key)

My lights ( nip into to my diary mate could be interesting??)
Attached File  IMG_20201005_193604.jpg   133.71KB   0 downloadsAttached File  IMG_20201012_144136.jpg   108.27KB   0 downloads

Well once its started lol!!

Take care bro really good thread ... Good participation
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