I went back to a 55 gallon freshwater tank which I set up couple of months ago after doing saltwater for years. After the set up done and a couple of weeks passed, I decided not to do fishless cycle and put in a few platys. I have a new eheim cannister and enough water flow from each side of the tank. A week later added two dalmation mollys and then a couple of lyretail mollys a week or so later - I know, probably too much too fast but discussed with LFS and a guy who seemed quite knowledgeable. I kept waiting for a spike and as I lost a fish every few days, my ammonia went up over 1.0 and then I started more frequent water changes. I went away for 4 days and found 2 more fish dead. I checked all parameters and PH had gone down to about 6.0 at most and ammonia between .5 and 1.0. I now have one lyretail left and got PH back to almost normal but still can't get ammonia down below 0.5. As of last night, PH was 6.8-7.0, ammonia .5, nitrates 0 and nitrites 0. I don't want to add fish until ammonia is 0 and figured I would have ammonia down to 0 after 17 days but no. Any suggestions for this nagging issue or is this normal and ok?