Difficult to keep track.

If you do keep the cool tube that close, make darned sure the inline fan is reliable.
Effective distance is what...4 feet? There is a point of diminishing returns and possible light bleaching, so keep you eyes peeled for damage.
Rusty Trichome Reviewed by Rusty Trichome on . Purple stem problem What is your experience level? Second grow Your Equipment: .1) Type and wattage of lights. ( tube fluorescent) .2) Distance from tops? 2-3 inch .3) Reflector type? ( 4 foot standard fluorescent dual tube .4) Is there a consistent fresh air supply? Yes .5) Do you have an exhaust fan and a circulation fan? Yes .6) What are the bulb wattages, kelvin ratings, and schedule? total 185 watts Rating: 5