i'm currently setting up my first reef tank, a 37g with a planned 10g sump, and i too was wondering about the number of PHs to get. i'd like to have maybe 20-30x turnover
going from what i've read, i'm thinking of two Hydor Koralia #2's (600GPH) positioned on opposite sides of tank facing the center. or perhaps 3 #1's (400GPH) with the same position but with the third flowing along the back of the tank behind the LR
. two #3's 850GPH each might work too...
a few people who've bought the 1's or 2's said they wished they'd get the 3's or 4's, but is 2400GPH a bit overkill for a tank like mine?
said that just 2 powerheads would do the job for me.