Thinking of changing powerheads, any ideas?

Hello all, in my current saltwater tank I have 2 Koralia 600's or 850's. Either way, I need more flow because of an algae problem and for overall flow in the tank because it seems a bit still in there. What kind of powerhead would you recommend? I was thinking of two Koralia 1350's. Is this too much flow for a 75 gallon tank and what would YOU recommend? http://ift.tt/1SHIrRh
Thanks All,
Thresher Shark