tvdao
Active member
I have a 150g with centered overflow. There is a Eheim pump (1262submersible) that power the 5 returns drilled high in the overflow. Is that enough flow, especially when they located in the center. If not, can I add a external pump (iwaki type) and have the intake plumb back to the sump rather than the tank itself. I haven't set it up but the previous owner added powerheads (3) in addition to the closed loop, make me believe that the closed loop alone wasn't adequate. Thanks for the advices.