I would think of adding a skimmer section into the design of the sump. Have a look at this site, Its a start. Hope I could help,and sorry you had to wait...
http://www.melevsreef.com/acrylics/sumps/chvy/chvy_sump.html
http://www.melevsreef.com/acrylics/sumps/chvy/chvy_sump.html