Hello, I've had my tank about 2 months, 100 litre. Slowly built up to 4 mollies, 8 neon tetras 2 honey gourami, 1 bristlenose plec, 6 harlequins. All went well till about 2 weeks ago when suddenly two of my mollies died and I found the ammonia was very high. Did a 65% water change, added prime and stabiliser and have done every day since, plus more big water changes every 5-7 days but I can't stabilise the tank. My honey gouramis are now looking ill. My ammonia levels are much better, but nitrite and Nitrate still high. I've used Tetra Nitrate Minus two days ago when I did another 50% water change. I think this was all caused by me inadvertently rinsing the filter in tap water after a water change just over two weeks ago. I don't know how to stabilise it and more fish getting sick is just upsetting for my son. The rest of the fish seem okay apart from gourami. Attached is the current readings on the test kit. Any help appreciated.