Expanding the closed loop for more flows

[tvdao]

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.

 

[Scooterman]

Is the Eheim return from the sump to 5 outlets?

 

[tvdao]

Is the Eheim return from the sump to 5 outlets?

Yes, through a pvc manifold.

 

[Scooterman]

Ok FYI:
A closed loop is just that, water is suctioned from the same source as the outlets, ie. suction from main tank, to pump & then returned to the main tank. Your dealing with a return from the sump that isn't a CL.
So most likely you would either leave that alone & add a CL which would increase your flow greatly or maybe add some other type internal water movement.
I used that same pump for a return & it worked great but I also had lots more flow added to the tank & mine was a 125g.

I would probably put the sump return on two outlets that go over the top on each side & use the 5 outlets for a CL return. This would be a little tricky to do with it already set-up though. Lots of options to consider, I'd read up & ask away before doing anything. Another words, what do you plan on keeping as in fish, corals & what types, how much do you plan on going with this? LOL better plan now that wish later!