Noisy drain to sump

[Lampshade]

What i did to allow some "adjustment" was drill 3 x 1/4" holes through the side of the cap into the pipe it sat on. I didn't seal the cap on to the pipe, and could twist it to open/close the holes. worked out great until I put a high flow pump for my return, lots of microbubbles in the duroso set-up.