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

Mcoocoo

Mcoocoo

Well-Known Member
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 :peace:
 
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.
 
Can u not turn it down to 400? I run a 600 in a 5x5 my 4” exhaust 200 cfm can barely keep up. I’d suggest a 400 cfm
 
Well 80 isn't so bad for lights on, I run in the 80s for majority of flower on purpose. I turn it down for the last few weeks(in my room where have control) but you can get by with that if need be. I'm honestly surprised you got it down to 80 in a a 3x3 with a 600. I run 315s in a couple 3x3 as well and they are in upper 70s majority of time(since I don't really have much control I honestly haven't had a thermometer in there for a over a year but when I did they were upper 70s). But I have a 6 inch fan cooling two 3x3 the fan is blowing thru the carbon filter which sets on the floor in between the tents (since only had one filter and fan for two tents) then on top of the fan is a y that has one 6 inch inlet and two 4 inch on the other side, from there I run 4 inch duct to the tents. It works great for me and I have plenty of negative air pressure( can tell from tents sucking in). It seems you can only cool a room so much with venting, how big is your fan and does it creative negative pressure on your tent that pull in the sides some what. If so your prob moving about all the air that you can from the tent. I have had success in the past using an intake fan to drop a few more degrees but it could have been situational since I had a window AC in the room the tent was in (really was before tents were common was a thing I built like a tent/room hybrid.)
 
Also I'm sure u have a smart phone you can download a lux meter for your phone, it's not entirely accurate I don't think but it's useful to help decide where the best place to hang light is.
 
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 :peace:
Click to expand...

Are you measuring temps with thermometer under the light?
 
Apalchen said:
Well 80 isn't so bad for lights on, I run in the 80s for majority of flower on purpose. I turn it down for the last few weeks(in my room where have control) but you can get by with that if need be. I'm honestly surprised you got it down to 80 in a a 3x3 with a 600. I run 315s in a couple 3x3 as well and they are in upper 70s majority of time(since I don't really have much control I honestly haven't had a thermometer in there for a over a year but when I did they were upper 70s). But I have a 6 inch fan cooling two 3x3 the fan is blowing thru the carbon filter which sets on the floor in between the tents (since only had one filter and fan for two tents) then on top of the fan is a y that has one 6 inch inlet and two 4 inch on the other side, from there I run 4 inch duct to the tents. It works great for me and I have plenty of negative air pressure( can tell from tents sucking in). It seems you can only cool a room so much with venting, how big is your fan and does it creative negative pressure on your tent that pull in the sides some what. If so your prob moving about all the air that you can from the tent. I have had success in the past using an intake fan to drop a few more degrees but it could have been situational since I had a window AC in the room the tent was in (really was before tents were common was a thing I built like a tent/room hybrid.)
Click to expand...
I have a Can Fan S600 and 6x16 inch filter combo, the filter creates some back pressure, I think without filter it is 270 cfm or so, not the best, but the filter works extremely well with it. I was able to get it down to 82 degrees withe a/c running. Also, exhaust is venting into same room, (venting out of window is not an option), I can live with 82, but would love to get it down to 79 max.. I do have dimmable ballast, I may dim it to 400. just sucks to wear on the bulb like that.
 
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.
Click to expand...
it is about 10 degrees above room temps with a/c running
 
Mcoocoo said:
I will say that it has a much bigger footprint from higher up, but doesn't it lose lumens and effectiveness the higher it is hung?
Click to expand...

I run one all the way up in a 4x4 which is slightly taller and have a drain table about 12 inches up so its its around the same height distance. I put 18 to 24" clones in and they finish around 36 depending on the strain. This pic had 4 shorties in the middle but they still turned out nice. Around 2oz each off 12 plants in a 3x3 tray.IMG_20190806_215322211.jpg
 
Gemtree said:
I run one all the way up in a 4x4 which is slightly taller and have a drain table about 12 inches up so its its around the same height distance. I put 18 to 24" clones in and they finish around 36 depending on the strain. This pic had 4 shorties in the middle but they still turned out nice. Around 2oz each off 12 plants in a 3x3 tray.View attachment 4393172
Click to expand...
That is all the way at to the top? They look great!!!
 
Last edited:
Mcoocoo said:
That is all the way at to the top? They look great!!!
Click to expand...

Thanks.. not my best grow had heat stress from this hot ass summer and a crappy ac that couldn't keep up and nute burned them a bit but they were decent. Love winter buds when they dont foxtail at all and I can keep it a nice 78 to 80. I use a 6" fan to expel it from a blockbuster hood to another room.
 
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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