I would use 2 penguin 350Bs in that tank, but what are you looking to stock with ?
did you want HOB? canisters? wet/dry?
general rule I use... not less than 6gph per gallon; higher is 'gooder'
2 pen 350s would give you ~700gph ish thats like just over 6gph/gallon
Turns the tank ~once per 10 mins.. Some like 10gph/g so the tank turns every 6~7 mins
again; the way you stock is a factor.