Chris~ I've had my best luck with growth for zoa's under MH's... Granted its only a 150 sunpod over my aquapod, but still... However I will mention that the color somewhat goes to crap... I personally like VHO's better for zoa's... Or T5's if they have individual reflectors, such as the TEK fixtures and whatnot... I sold my 2x250w HQI's over my 75g to be replaced by a T5 fixture... Since I sold the HQI's before I received the fixture, I used 4 VHOS 2xSuper Actinic, 2x Actinic White... I have liked the way they've performed enough to keep them on there for a while (3 months)... I will be removing them here shortly to put on my 120 and will have to buy my T5's... I'll be going with an 8 bulb fixture with a bluer spectrum to go over the 75g... Hope this helps...