I've recently set up a tank for my little boy as he loves fish. I followed all the instructions and left it the correct amount of time and got a black moor today. It was fine for an hour or so then went and sat on the bottom of the tank. I read a few threads and came to the conclusion of ammonia or nitrites, so i got a pack of test strips and tested it. Everything is ok accept the ammonia is sky high. I did a 50% water change to get almost same result. So I tested just the water and its in my tap water. I'm in UK and have used tap safe (which was recommended by my fish retailer), but its not bringing the ammonia levels down. What can I do? What's the best product to solve this?