Hey guys, I'm eventually going to need some more flow in my tank, so I'm doing some powerhead research. I have a 58g tank that measures 36"x18.5"x21". It seems pretty clear that vortech is the way to go, but I was wondering if I would be better off with two mp10s or one mp40. It seems that I would have more flow options with the two mp10s, but one mp40 would be more useful once I upgrade to a larger tank. What do you guys think? Would one mp40 be sufficient?