All F'ed Up

[Animalhouse]

Hey Guys could really use some help here. A year ago I started my first planted tank at work. It’s a 38 gallon with soil substrate 4” covered by small gravel 2” I have Malaysian drift wood with java moss, fern and anubius. I also have Val, Cryps and Swords growing as well. For fish we have 10 rasboras, 3 cory cats, 3 otocinclus and a dozen cherry shrimp. The whole thing is filtered with a Fluval 404 and lighted with PC’s. Everything was going well for about 8 months then we had slime algae. So I did more water changes and carbon etc and eradicated it only for two months later to have gray water that won’t go away. I have tried up to 2 ten gallon water changes weekly, polyfilter in fluval, and more carbon. Water is clear for a day or two and goes back to cloudy. A couple of things to note, Soil was taken from a greenhouse with no additives but was not sterilized, this soil has also been magically rising recently from under the gravel and third we have large mounds of feces as big around as a quarter and up to half an inch tall. I don’t think any of the fish would crap like that. Any Ideas, Invert in soil, Bacteria Bloom, Act of God? Dunno!