Problem with Return Pump

[tomocean]

I tried this on reefs.org without any luck. Hoping for better luck here. :-) I have a problem with the return
on a newly setup 75G. I'm using a Gen-X MK4 pump with an Ecosystem sump. The problem is that the return pump is constantly spewing millions of tiny bubbles with each
return cycle. I was thinking that maybe it is because the sump and pump are on the same level. Should the pump be lower than the sump? Any and all thoughts appreciated.

[Pikaboo]

The intake of the pump should always be below the water line.

[Ceorl]

Sounds like it might be cavitation, what is the plumbing like and what's the flow rate, etc?

[Greg3333]

Any small air leak in the plumbing can also pull air into into the line.