Using Hortilux and no problems with a 600 Galaxy digi, huh? Its not listed as being compatiable on bghydro site, hmmmmmm. I'll give them a call later.

Fan size is determined by flange size on hood, not CFM size. Most sealed lights you can get with 6" or 8" flange. That would depend on how many you are going to daisy chain together.

One other tidbit, put fans on their own breaker so if lights kick their breaker the fans keep running to cool lights.

Oh, and I prefer 240 versus 110. Draws less Amps, but uses same amount of power. Unless you are an electrician (or have one as a buddy), 240 is not practical for most home growers. Dont find many houses with 240 sockets mounted in every room.

Goin green,
b0nger