subsonicdrone

could be bunching up or choking
might only be from the cold...

personally i use HPS
the HPS bulb is 155 000 lumens (1000W)
MH bulbs are 115 000 lumens (1000W)

people may argue over whether lumens are a good measure
or if the spectrum is ideal and what not but you get a lot of punch from HPS

people have told me that MH run hotter as well

you got both bulbs with youre kit right?
look up the #s on the bulbs

but then again i have never had multiple leafs per week unfurl as some people claim

Richard says the best indoor set up are T5's side by side for 100% coverage
probably works out to near the same watts per 4' x 4'
but a more ideal spectrum

so there you have it... T5s are the best but HPS should work too