How high to hang 600 watt HPS in 3x3x7 tent?

Mcoocoo said:

I got it right up there at the top, now canopy is @ 80, with fan over tops, but ambient in the corners are @ 91 I'm starting to think it is a losing battle

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Get an oscillating fan in there to circulate the air better.

PJ Diaz said:

Get an oscillating fan in there to circulate the air better.

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thanks for replying, I do have one in there now, I was able to get ambient temps down to 82, in fact everything is right at 82 in there. Not so bad, could be worse. I need to bring down room temp outside of the tent, then I should be able to bring it down to 78-79 hopefully

BostonBuds said:

I think the temps will go up no matter what height you hang it, you have to focus on air exchange getting the hot air out and cooler air in. Light height has to do with burning the plants being too close. What do you have for an exhaust? With the high temps during summer i actually leave the closet door where i flower open and an oscallating fan blowing into it, it does work at keeping temps within 5 degrees of the inside temps. Lights out I just shut the door and have the carbon fan running for air circulation. It was either that or buy an ac.

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I have a 6 inch Can Fan S600 attached to a carbon filter. I was able to get the temps within 8 degrees of room temp outside tent. I hung it straight at the top and light spread from the 600 in the 3x3 soaks the plants pretty well

It's really hard to effectively cool a batwing type reflector in a small space. I'd suggest investing in a vent-able hood.

You need to find somewhere else to send your heat if your trying to get it lower. I still say you will be fine to run at 82 as that's roughly where I keep my room on purpose except for the last few weeks. Even if you can't lower it the last couple weeks, you will still yield more than with running it at 400 watts. It might just be a bit looser bud structure. Trust me I wouldn't vent out of my house for a long time cause I was worried about the smell but that was completely backwards from how it works. The smell never has a chance to build up and get over powering like it does when it vents back into house. Think if it like this the exhaust coming out has been scrubbed to be prob 95% or so clean air and it doesn't have a noticeable smell when you blow it outside. But if you blow back into the house that 5% dirty air that you couldn't even smell builds back up to be quite stinky. Also finding a suitable place to vent will lower your ambient temps in the room the tents are in (since your not pumping out heat into it) and allow your tents to run cooler.

If you measure air temp correctly it wont matter what height you hang the light, though it will affect radiant heat but it not so much of a worry.

That's why I asked if your thermometer was directly under the light, because then it can make a difference to your reading, though not really to the air temp, since radiant heat will warm a thermometer up pretty easy, giving false air temp reading.

It isn't as much of an issue with a probe, since they are usually pretty small and are less effected by radiant heat (light).

Anyhow two ways to go about this. (well two easiest ways)
1.Use an air cooled hood. That's going to be the cheapest way to make a big difference in air temps in your tent.
2. Buy a bigger fan for more air exchange, assuming the heat leaves the room like it should.

I agree with Apalchen, 82 wouldn't worry me either. But at the same time a reasonable trustworthy air cooled hood is cheap as chips and very effective.

with A/C, I have been able to get the temps down into the mid 70's with the light hanging between 20 - 24 inches above canopy, I do not dare to hang it lower, at the risk of frying the tops in the 3x3 tent. Canopy temps are even lower on colder nights 70 to 73. Anyhow, venting out of the window here is just not an option, as much as I would like to, I cant. I would have bought the vented hood if it was an option, but thx for suggesting it. I do understand what you mean about ambient temps in the corners. I have a small plastic hygrometer placed in the corner where the hot spots from the reflector hit and it reads 90 degrees, but 2 inches over I have a hanging thermometer reading 78 ambient. It makes more sense that ambient is 78, because canopy is 75. I have a fan blowing over and under the canopy, which has been lollipopped to avoid humidity and airflow problems. All in all, the 600 watt is working out great, I wouldn't even bother to buy a 400 for flowering, for veg maybe, but not flowering. Thx for the responses

Did you do the hand test? Just hold your hand at the canopy and if its not uncomfortable for your hand then its ok for the plants

Gemtree said:

Did you do the hand test? Just hold your hand at the canopy and if its not uncomfortable for your hand then its ok for the plants

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yeah, my hand feels cool at top of canopy, leaves are cool to the touch too. It's funny, I actually almost fried the top of my head under that light, it felt like I was at the beach.

Yea I run my 600wair cooled hood in my 3x3 at about 18” above canopy and I only run my HPS in the winter to also act as a heater lol it’s hard to keep my temps at 76 degrees in the winter. Even with the light on my space heater is kicking on every 5 mins to keep temps at 76. I use the Titan day/night temp controller. I could actually bring the light even closer but I like the spread I get at 18-20” above canopy. I have a 6” carbon filter about 350 cfm and in the summer I’m either growing outdoors or using my LEDs where I don’t have to combat heat.

Mcoocoo said:

How high above canopy should I hang 600 watt HPS with econo wing? I would like to keep it at 20 inches but I can't get temps under 80 even at 27 inches, Can I hang it a bit higher in a 3x3, due to the spread? They say a 600 HPS will cover 4x4 no problem, so I am thinking that in 3x3 that it could hang higher and still get same intensity. Just wondering if anyone else uses 600 in 3x3 and has same type of problems. Thanks in advance

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i have the same light point a fan directly at it and keep it at 20 or 22 whats your humidity? maybe swamp air to cool the tent if you live in low rh

NYFlowerpower631 said:

Yea I run my 600wair cooled hood in my 3x3 at about 18” above canopy and I only run my HPS in the winter to also act as a heater lol it’s hard to keep my temps at 76 degrees in the winter. Even with the light on my space heater is kicking on every 5 mins to keep temps at 76. I use the Titan day/night temp controller. I could actually bring the light even closer but I like the spread I get at 18-20” above canopy. I have a 6” carbon filter about 350 cfm and in the summer I’m either growing outdoors or using my LEDs where I don’t have to combat heat.

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i run 2 side by side open reflector in the winter it stays around 77 at night lights out i put on a heater my girls love the light

Mcoocoo said:

yeah, my hand feels cool at top of canopy, leaves are cool to the touch too. It's funny, I actually almost fried the top of my head under that light, it felt like I was at the beach.

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the back of my head gets sunburn on water day i have 2 600s and have to crawl under them lol

seriously be careful dont get spray or oil on the bulb i clean mine once a week take it our and inspect it