Hi everyone. I'm having a really hard time clearing up my water in my new 55 gallon. Fluval dirt substrate, i let the tank cycle for about a week before adding fish. I currently have 8 corydoras, 1 rainbow cichlid, 2 gourami. In terms of water parameter benchmarks, all the levels are pretty much perfect. The local fish store told me to put purigen in the filter, which i did and it seemed to help a little but the pack got very dirty. Any helpful advice?