should have named this whats the highest i can keep my light? so im about to start my first grow. im going to be using a 600w hps light with a 400cfm inline fan air cooling it (over kill, i know). the ceilings in here are 8 feet and the tent im using is 7 feet. i have 5 gallon buckets (15 inches tall), ac hood (8 inches), and i plan on keeping the light 18 inches above the plants. so thats 41 inches gone right there, giving me 43 inches. so whatever distance i need to keep the light from the top of the tent will be taken out and the remainder will be the maximum height for optimal conditions.. i prolly didnt need to run you all through that but its just so darn exciting haha. anyways, again, 600 watt hps lighting in a 400cfm air cooled hood, 7 foot tent 1 foot below the ceiling, whats the closest the hood should get to the top of the tent? it cant touch it, im sure ive heard bad things about getting too close somewhere... but where?
The top of the hood might get warm to the touch but it shouldn't get hot enough to melt something or do damage with the fan cooling it. An inch or two from the top of the reflector to the ceiling is fine if need be. A 600w lamp offers, at most, 90,000 lumens. At a distance of about 32 inches from the bulb the lumen levels are too mild to encourage healthy growth. The ideal zone to grow in beneath a 600w lamp in an AC reflector is between 8" to 28" from the bulb. Taller plants should be pruned of the under growth because it is too far from the light and obstructed by the upper growth. This allows the plant to focus its attention to the properly illuminated area.