When I said too close together I just meant vertical distance between drain intake and emergency intake. I'm not sure how some people tune their valves so exactly but I've always found the water level will creep slowly up or down no matter how careful I am. So I tune it so a tiny bit trickles into the emergency always. If the emergency was too close to the drain (water height above the drain was too low) it might suck air. All I meant but maybe I misunderstood your issue.

I'd also try and use the smaller hole as your drain before drilling though.

Thanks lastlight , at this point it is all taken down for painting and upsizing of the pipes. I have 2 or 3 easy to try options to try and fix this including changing drain and emergency pipes and because of all the advise I am not in such a rush to do any drilling.

Appreciate the input.

Updated starting here.

http://www.canreef.com/vbulletin/sho...18&postcount=9