ASM G3 Protien Skimmer

[byee]

I'm looking for advice / help setting up my ASM GS skimmer. I've modified it by adding a gate valve. Even before the mod, it seems to like skimming water. I very seldom get any dark stuff in the waste cup.

I do remove the cup once every 2 weeks for cleaning the inside where the bubbles rise to have a layer of crud stuck to it. Its some times 3-4 m in thickness all around the cup. Its skimming but the dirty stuff is not finding its way into the waste cup.

I've placed it in my sump with the skimmer elevated about 4 inches. The plumbing from the pump has been modified to accommodate the increase in height.

The needle impeller does have may 6 missing teeth. Will this impact the skimmer ??

I was thinking drilling out the skimmer for 2 wooden airstones to increase the bubbles in the chamber.

BTW, I only have about 10 chromises, 1 naso tang and a bunch of soft corals.

Any opinions on what the problem may be ?? Will adding airstones to the chamber help the improve the functionality of the skimmer. or is it because bio load is very low ??