Logan,
Don't give up. I has a bad case of it a few years ago and it took me about 6 months to cure it. But it was worth it.
Check your RO/DI water and be sure it has zero TDS. You can get TDS meters for under 30 bucks.
Can you add a filter sock to your sump? If so, get some from Fish and Other Itchy Stuff. Put them in and stir your sand bed regularly. I think the stirring of my sand bed helped to get the majority of my debris out of the sand bed. Be sure to clean your filter sock at least weekly. Filter socks are only a few bucks.
Keep doing your water changes and manually pulling out the cyno. It takes awhile, but don't use chemicals.
Good luck,
Chris
PS - Your power compacts are now over my 20 gallon quartine tanks and working great.
Cheers,
Chris