I just ordered a 125 gal and i'm getting cannister filters for it. My simple question is, the filter is going to be a Rena Filstar XP3 or XP2....if i do the XP2 it would deffinatly mean i'm getting two of them and placing them at opposite ends of the tank....the xp3 is rated for tanks up to 175 gal. Would one XP3 be enough for the 125? Or would it be better to just get for the extra 20 bux Two XP3's instead. I dont see how 2 XP2s would benefit b/c combined they are still less than one XP3. What do you all think?