Reduce bubbles when return sump back online?

[Lake75]

I turn off my return pump whenever I feed my fish. But when I turn it back on, during the first seconds or so, it pushes a lot of bubbles into the display, sometimes causing problem with my clams. I guess these bubbles are from the air that is trapped in the plumbing after the siphon is broken. Is there any way to reduce/eliminate this? Will a check valve inserted in the return line solve this problem? I've never used a check valve and heard that they reduce flow and tend to fail after a while, so I would prefer to avoid using that. --Any suggestion? Thanks!

[reef_doug]

Just a guess, but if you have a Lock-Line on the return above the display surface it might be sucking air back into the return pipes.

Good luck,
Doug

[Lake75]

That's a good point. My lock-line returns become half exposed to air when water level drops below the overflow box. I will lower it and see if it fixes the problem.