What size piping is your "durso" made out of?

All plumbing is 1" except the drain which is 1.5" there is only 1 drain and 1 return. throttling back the pump doesn't make a difference

The durso pipe needs to be larger than the bulkhead size.

ie. 1" bulkhead --> 1¼" or even 1½" standpipe

Hmmmm, durso's are usually 1/4" - 1/2" oversized compared to the bulkhead, maybe this is the "problem"?

Is your bulkhead 1" or 1.5"?

*Edit* lol, guess we were typing at the same time.

I would build and actual Durso, oversized.

If you look at this pic

http://smg.photobucket.com/albums/v6...Anch=imgAnch11

mine is 1 1/4" that steps down to 1" at the bottom where it hooks to my bulkhead for my return...

Sorry the "drain" shoulda been durso and it is 1.25 not 1.5

Have you tried drilling the holes in the pipe as it enters the sump like i posted at the top of the page???