I have a 55 gallon freshwater tank that I set up using quick start. I ran it for a week without fish and then think I took some bad advice from a local pet store saying I needed to add fish to get things going. I had 6 hardy fish, I think they are some type of tetras (???), I'm down to 5 now--my nitrates, nitrites and ammonia are high. I did a partia water change, retested the water and still high. I heard some good reviews about Amquel Plus so ordered some and is due to arrive today. Is it okay to add this to a fairly new tank that has quick start added to it. I have an aqua clear 70 filter on the tank that I can add different media to, is there something I can add to the filter to get the water levels to where they should be? Thanks for any and all advice. I hate the thought of losing any more fish, two of them aren't looking very well