ive had my tank running for a good 2 weeks. Dechlorinated with Prime then used Fritz Zyme turbo start. I put 2 Synodontis catfish in it for about 2 weeks and they did fine. Introduced some glofish and that's when everything went to . Three at a time the glofish started dying. Then the cats died as well. Did a 50% water change thinking I may have gotten a parasite from the glofish. Then I reset the tank with more prime and turbo start and let it run for about a week When I checked all my levels ammonia,nitrate,and nitrate were all zero. The pH was at least 7.6 Now I have Molly's and they are dying in groups of four or more. The only thing I noticed them doing is they're all staying at the bottom of the tank they are not eating much and when they die they sink. The tank is 36 bowfront and I'm using an EHEIM 250 for filtration and my substrate is aragonite. Please help. I have never had this much trouble with a tank in my life.