I'm using filter floss in my sump right now to rid myself of the same issue you're having.... I just placed the floss in between 2 of the baffles and monitor it so I don't have a back-up.
It's working ok. Are you using a nylon filter bag of some sort on your sump input side?... I'm gonna put on one the end of the overflow line.
I too kinda wanna know if there is a small mechanical filter that I could get to put the floss and some carbon in.... It just needs to be small enough to fit, not necessarily have a huge through-put, just enough to do the job.