I live by farms and a swamp and I have had problems with my water. There is something in the water and it isn't nitrates but it kills my fish. For right now I have been using a pur 3 stage faucet filter for a few months with no problems but it's so slow and expensive. Is there a house filtration unit I could add that would work? I don't want to do ro. I don't have room and I have a lot of tanks. I have seen some filtration units that you can add different cores too but I don't know which one would work? Any help would be great.