1. Do you recommend attaching a carbon filter to this setup(2 hoods), or do you think it will be too much load on the fan for such a large tent.(even though the 449cfm can handle an 8x5x7 tent)?
2. Is it more efficient to have the 6" for exhaust only, and have another, smaller fan doing odor control from pulling a carbon filter from within the tent?(this seems like a better option to me)
3. I am going to use the two 600W HPS hortilux eyes, but probably supplement with a few panels or UFOs of LEDs. Currently I have two 90W flowering lighthouse hydro UFO and a 240W blackstart LED panel. Aside from the LED heights, what would you recommend for a proper distance of the two 600W from canopy? Also, how far do you think they should be apart? I figured an equidstance from eachother in relation to the tent, but I would like to hear your input.
4. Any other recommendations or concerns you may have woiuld be appreciiated. Normally I do much smaller scales, but I am doing it in a bigger tenet now becuase it will just be so much more efficient.
Thanks to you for your response! I look forward to hearing from you.
_Snafu
SG15 hit em all on the head, I'll just add a few words.
1. Your fan should cool the lights no problem. Yes a carbon filter is necessary if you are trying to control smell. My hut stayed very well
concealed as far as smell goes until I opened the zipper.
2. I had separated ducts. One going straight through the lights and one exhausting out the top. If you recall though, in the very beginning
I also had a separate intake coming in direct from outside, this was until I bought a window unit airconditioner and just cooled the room
the hut was sitting in. Basically the room the hut sits in acts as a lung. The hut exhausts heat from the tent and cleaned air through the carbon filter
and the airconditioner cools it before it is taken back in to the tent. I like dedicated ducting.
3. I'd have the two 600's equally spaced over their respective 4'x5' area's and have the 90 watts evenly distributed either between them or around the edges.
I am trying to picture how it will fit together with the different lights, and if you remember from my grow tent I had the two 600's with the T5's on the outsides.
4. Congratulations on stepping up to the larger space, it's a lot of fun. Definitely think about the intake for offsetting your negative pressure. Negative is good, because
it guarantees you will not have air escaping except through the filter, which means no smell. But too much negative pressure stresses the fan and could stress the seams
of your tent over time, weakening the integrity.
For spacing lights, I like to give my plants roughly the same light energy that the sun is estimated to put out. Roughly 10,000 Lumens / square foot. A 600 watt light puts out 90,000 Lumens / foot at a one foot distance. Using the inverse square law, at two feet (twice the distance) it becomes 22,500 (1/4 the strength). At three feet from the bulb the light decreases to roughly 11,250 Lumens.
Here is a really report on what happens to the photosystems of the plant when there is too much light. It basically explains that yes, plants in nature experience too much light basically everyday of their life. The sun puts out nearly twice as much light as plants require for photosynthesis. So what do plants do with it? They dissipate it as heat. They are very good at doing this but it does require energy to manage this function which would otherwise be used for other plant processes.
This here I find to be a key statement
"
At low irradiance levels (low light levels) when photosynthetic membranes are in the high-efficiency state (Fig.1), leaves demonstrate an efficiency (i.e. quantum yield) for CO[SUB]2[/SUB]
reduction that is close to the theoretical maximum (13). This exceptionally high efficiency is possible only because the amount of light absorbed by the antenna serving the two photosystems is closely balanced. Thus it is inescapable that at high irradiance levels when PSII photoprotective thermal dissipation is engaged, PSI will be absorbing many more photons than it is receiving electrons from PSII."
They are saying that at low, equal light distribution levels plants absorb the most light and use the maximum CO2 theoretically allowed. In high, unevenly distributed light systems one photosystem will be absorbing higher levels then the other, lowering overall efficiency.
When I see people sitting with their 600 watt hoods at like 6 inches to a foot above their canopies, and I even see people with 1000 watt hoods doing this, I cringe. People are blasting their plants with 50,000 lumens or more if they were to actually do the math. But there are still many people arguing that more light is always better with no adverse affects as long as you have the temperature under control. I don't care if you have a 72 and 50% humidity at 1 inch from the bulb, it should never be that close. (unless it's fluorescent.)
Matter of fact if you want to see someone rage at me over my light distances just a couple of days ago, check out
this thread. The dude gave no scientific evidence to back up his claims, basically directed me to forum grows that backed up his theory that the light always needs to be closer. The truth is, there is more than one path to get to Rome and your grow will definitely take some tweaking and time. No two are the same.