how close can my 400w aircooled get?

blizake54

Active Member
i have a 6' air cooled tube with 6' ducting and a 6' inline fan on medium with controller. they are about 6 inches from the bulb and its 73 degrees right there. can i put them closer?
 
I had my 400's almost that close without being aircooled. Remember, you lose footprint size the closer you get to the tops. I think that after a certain point, you get to a point of diminished returns.
 
depends on room temp, Good way to do it is put the back of your hand where u want to guage it....and u dont want to get them as close as possible when vegging, only flowering. U want to put the light where IT WILL BE THE WHOLE TIME OF HARVEST. u do not want to put the light as close as possible through vegging.
 
1) stop being paranoid
2) stop being OCD
3) just keep your light levels even over your canopy as Jack said ;)
 
i wouldn't put it any closer than 5 or 6 inches. i have a 400w hps and i let them get within 3 inches because they weren't showing any signs of stress and i got a bunch of bleaching of chlorophyll. i didn't think it was possible with a 400 but it is. i never let them any closer than 6 inches or so.
 
Another thing to consider, you're losing up to 25% of your light to that clear piece of glass. So it's trade off. Less light, but closer, or full light and a bit further away. I know that I, personally, will never buy another air-cooled hood again.
 
I hear the glass also bsorbs almost all UVB which has been shown to benefit plants. As for the original question. I use 400w metal halides for veg and they can get really close. Trying to veg a mother, I had them growing into the light and it was only until the plant touched the glass that it got burnt.
 
That's why I ain't replacing the air cooled hoods that the cops got. I had bought 4 Sun Systems, and after reconsidering everything, I'm better off with open hoods. I could buy 3 hoods for what 1 piece of fused silica or quartz glass would cost. They come with cheap leaded glass.

In reality, your average loss is only about 20% (It CAN be as high as 25%), but that is STILL a significant amount of light, more than enough to offset any gains by getting closer to the tops, IMHO.
 
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