Ok. I am lost, I do not know what is killing my fish. I did some water changes and I had a .5PPM ammonia, and 1PPM nitrite spike (for one day), but I no longer have any. I lost a clown loach, a few cardinal tetras and my beautiful dwarf honey gourami. Also, my clown loaches have very red gills still despite my levels being unmeasurable. I am at a loss as to what is wrong. My clown loach had a big belly when he died. So did my gourami. My nitrate is <5PPM; currently ammonia and nitrite are unmeasurable. I removed one of my canister filters, it was my cascade 1500, it had so much bypass, so it wasn't that useful. I have since learned that it was what was really stinking. I dont know why. Either way, I removed it and now my whole house stinks. Advice? I am overdosing excel slightly (2x dosage), and it is killing my stag horn algae but I am not overdosing it by much. Feedback?