Hi, I'm looking for some ideas on what is going on with my fish tank. My Amonina levels are terrible. I haven't bean able to keep them at 0ppm at all. The nitrite and nitrate are at 0ppm but the amonina keeps spiking. I keep three freshwater stingrays in a 230 gallon fish tank. Two are bigger rays and i have one smaller ray as well. I have two eheim that are rateted for 500+ gallons also have a eheim pro 3 rated at 160 gallons and an fx6 fulval rated for 400 gallons. The fx6 is full to the top with media and the 2 eheim 500 gallon has about 9 lt of media in them. The meadi is the pro 2 substrate from eheim. The media in the fx6 is mixed media not to sure what brand it is. I think there is three different types in it. And i also have what ever media comes in the pro 3. Also have a bottle of purigen inside the pro3. I do a water change everyday but i have no luck trying to keep the Amonina at 0ppm. Does anyone have an idea wbat to do?