What to buy

[Reliable1]

I am about to purchase a T5 fixture and need advice. It is between a 48" 4x54W SLR T5 Very High-Output Retrofit Kit w/ Bulbs or 48" 6x54W SLR T5 High-Output Retrofit Kit w/ Bulbs. I currently have a hang on refugium that blocks half of the back end of canopy (some humidity occurs). I know that i can overdrive with Very high output ballast. So would i get more out of the 4 x 54 very high output or the the 6 x 54 high output. please give me your suggestions. Also what bulb combo to purchase.

Thanks

[DarG]

I would go with the 6 bulb because the 2 extra bulbs with reflectors give you more spread and more bulb combinations allow more color choices. The wattage is almost the same so heat isnt going to be much different. Bulb replacement cost differences are not going to be much different either way assuming how well you cool the overdriven set up. The Overdriven lamps wont last as long regardless. In your case, the only real advantage to overdriving is, IMO, the super actinics (UVL brand) look pretty good. Non overdriven I think that super actinic T5's look weak. But that assumes you even plan on using them. Anyway, the only reason I would overdrive T5 was if I didnt have room for enough bulbs at HO levels or if I was targeting using UVL Super Actinics only for color supplementation.
I have run T5 both ways. I only have room now for two T5 to supplement my halides so I overdrive them but otherwise, I would just use standard HO ballasts.