I have a similar set up, except i used a rubbermaid tub instead of a glass tank and put a bulkhead in. I have my skimmer in the tub with a denitrator coil. I have my chaeto in the sump. I am going to have to start removing the bioballs, or at least take out the screen and drop them into the water.
unfortunately, I raised the sump when i drilled the hole in the rubbermaid, the sump already had an outlet, for an external pump I assume. So I have a high level in the tub, and the level in the sump is the bottom of the bioballs. I may spend the $10 on a new tub and do it level so that there is more water in the sump too. i might take out some of the rubble so my chaeto tumbles.