I have a 135 gal. reef ready tank (freshwater for now) and a 35 gal. sump tank with bioballs. I got a Mag Drive 12 (1200gph) and a 25 watt uv light. My tank is stocked with (2-12" Oscars and 3-4" Cichlids). My problem is high nitrate & ammonia levels but my nitrite levels are low. (I always get Nitrite and Nitrate confused so this could be backwards). I have heard bioballs contribute to this problem? Any suggestions on what to put in my sump tank to help control this problem would be greatly appreciated.