I'm looking for some recommendations for powerheads for my largest tank, which is 8'x4'x4'. I've got quite a bit of rock work along the back of the tank and there are plenty of dead zones in the tank now. The only circulation at the moment is the return from my sump which is from a Water Blaster HY10000 (2600gph). For those of you with larger tanks, what would you recommend on a modest budget?