36 x 20 x 63 tent with 400 watt hps NEWBIE

So I've been scouting through these forums trying to find the best advice on growing my babies but i figured the best help i could possibly get would be to start my own thread, any input is greatly appreciated.

I have a 36 x 20 x 63 inch tent setup in half of my closet with about 5 vents (2 on top, 3 on bot). I am considering purchasing a 400 watt HPS and MH with cooling tube in the next week. I'll have the cool tube connected to an air duct running directly out of the top for ventilation with a 240 cfm fan pushing air out.

I am wondering if this will be sufficient to keep the temps cool enough? Will I need another 240+ cfm in one of the bottom vents to pull air in? Since it would be in my closet, I would keep both sliding doors cracked a few inches on both sides (One for air coming in and the other for air going out).

I am also curious on how many plants i'd be able to fit in there and in what size pots (I was thinking two 5-gallons but the more the merrier).



Please any feedback would helpful. I can supply more details if needed. Thank you.

I would (and did), get a higher CFM fan. I have a 400W as well in an area a little narrower and a little longer than yours. I'm keeping it (the bulb) cool with a TD150 fan. The room/space, it needs an AC to stay cool... at least in these summer temperatures. I have a separate, smaller fan handling the exhaust.

My advice to you is to read up more on ventilation/room design (there's a good thread over at icmag concerning ventilation, search on google for "Ventilation 101 icmag"). Also, do some dry test runs once you get the lamp. Find out how much hotter it gets some distance from the light, let's say 12" from the light. Take that information, coupled with the information from the Ventilation 101 thread (specifically the chart showing CFMs to Temperature deltas) and figure out if that fan is good enough.

Another, more general tip regarding light exhaust fans, buy a fan that is more powerful than what you need. You can always buy a rheostat/variac and turn it down for $20-40, but getting jsut a bit more power will cost you another fan entirely.

Also: If I went with a 250 watt Mh/HPS could I get by with just a simple 240 cfm inline fan? It's in the closet in the room I sleep/live in so simplicity is semi-important, however, smell is not .

is it an axial or centrifugal inline?

Since you're going to be right next to it, I'd say your #1 is noise. I personally don't mind noise too much as I've gotten used to it from being in server rooms and dealing with computers, but it might bother you to sleep next to something making 60+ dB. With that said, I'd go for an axial inline. These are pretty quiet and you can find other threads mentioning them if you want opinions on it: https://www.hvacquick.com/products/residential/AirFlow-Boosting/Inline-Air-Booster-Fans/SP-TD-Series-Inline-Fans. If you want to see how big they are, find my journal and look for the picture with Timewreck/SLH. You can see it mounted on the top.

I have 2 of them, each cooling a 400W. I don't vent my room and light together though, so their only purpose is to cool the light.

I just noticed by click that link that they're max 293/lo 218 CFM. I think 240 should be fine. Just make sure that it doesn't drastically drop once the static pressure rises.

I have a tent that size and run a 250watt no cooltube 4-5" away from canopy. as for size you could fit 6 2 gallons easy. I Exhaust out the bottom and intake from a ac vent with ac on and run around 79-82 (south Florida tho) I have 2 of these fans as intake and exhaust. Alot of people complain about inlines if they sleep in the same room, I have these too and can sleep just fine. I would do exactly as you said with a 240 cmf fan with the 250 but atleast a 400cmf with the 400w hps in there

JayJayDaStoner said:

I have a tent that size and run a 250watt no cooltube 4-5" away from canopy. as for size you could fit 6 2 gallons easy. I Exhaust out the bottom and intake from a ac vent with ac on and run around 79-82 (south Florida tho) I have 2 of these fans as intake and exhaust. Alot of people complain about inlines if they sleep in the same room, I have these too and can sleep just fine. I would do exactly as you said with a 240 cmf fan with the 250 but atleast a 400cmf with the 400w hps in there

Click to expand...

any pictures of the harvest from the 250 watt grow?

I'm still kinda torn between the 250 and the 400. However, I am more leaning towards the 250 just because I won't have to deal with heat as much. I might add a few CFLs near the base of the plants as well(?). I also fear that the 400 watt with sufficient heating might be a little too loud since its only a few feet from my bed. I'm a heavy sleeper but I have no idea how loud/hot it could get.

The 250 watt sounds a little more reasonable in terms of price and the electricity bill especially for my first time growing indoor.

Thanks JayJay and Yano for the previous posts(any extra input would help in my decision making!). To the rest of RIU, any words? Thanks!