distance from tops with cool tube

[mooz]

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[MrMcBean]

depends on how much light the strain can handle but you can get as close as 10 inches or closer.
experimenting wont hurt.. Lightbleaching isnt that dramatic when you watch out for it..

peace

 

[etinarcadiaego]

I'm using an aircooled reflector (not cooltube though) and my light is about 4" off the plants and they love it. I vegged with it about 2" off the plants since I could maintain an even canopy. That just my exp. though.

Someone else posted this, and I saved it since I thought it'd be helpful:

 

[festivus]

I use a cool tube in a refrigerated box with a 250 hps and 6" axial fan. I get bleaching if the plants touch the tube, even if the box temp is in the 70's. The plants can be an inch away with no problems, it's only when they touch the tube that I get bleaching

 

[mooz]

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[mooz]

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[BLUNToPOTomuss]

I can grow my girls around my tubed 400 with no problem, and have yet to experience bleaching. I DO NOT use mylar though so that could be were Im getting away with it. Im using a 265 CFM active air blower pulling through my tube and pushing into a scrubber. I hae a 2x2x4 cab.

As for distance.... I leave it at approx. 3-6 inches away. I start at 6 and move it back down when it grows to 3 inches away.

If you use .3-.4 CFM per watt for bulb cooling only you should have no problems, IMO.

 

[xcrispi]

I run multiple 1000w hps inside 8 in. diameter cooltubes cooled by a 1050 cfm Can Blk Max Fan and I can get w/in inches once plants are mature w/o bleaching , heat stress etc...
Crispi

 

[etinarcadiaego]

@ mooz. I exhuast my cab, which is 2' X 3' X 6' (36CF) with a 6" centrifugal blower fan rated at 435CFM.