Quote Originally Posted by BlueBear
This is what I always preach, good topic. I have my 400 about 4 inches away from the little ones in veg with an air cooled and with the air cooled on the 1000W I go about 10 inches, I could go closer, but I don't want to loos the ft print and I have noticed that some plants can't handle the lumen intensity and the chlorophyll in the bud will become bleached and turn white.
Adieu
bluebear i love that name,not to get off the subject,but how are able get that bulb so cool.can u tell what Ur grow area and ur fan cfm's because i a small grow cab and i get under 87 constantly. the cab is only 60'' height,15 deep and 29 wide ,so roughly 3.3 sq ft and im running a 400w hps home cool tube with that 80 cfm in-line duct fan.I have it pushing thru the cool tube and out the other side. im trying cool the bulb and exhaust it at the same time and also I have a 80cfm for the intake and 240 i believe for cab exhaust three fan what am i doing wrong.
smokybear Reviewed by smokybear on . Light intensity: Why to keep lights as close as possible Light intenstiy = Total Light Emitted / ((4 x pi) x (radius^2)) And light intensity decreases by 1/x^2 where x is the distance. So like if you have 135,000 lumens at 1 foot, you increase that to 2 ft, you it would be 135,000 x 1/2^2 which is 1/4 so basically one fourth of 135,000 = 33,750. Add one more foot, 135,000 x 1/3^2 = 135,000 x 1/9 = 15,000. Crazy huh? Thats why the top bud always is so big and the bottom ones are smaller, cause they get a lot less light. LST'ing takes that Rating: 5