I added 3 Clowns to my 100 litre tank a few days ago, before I added them my ammonia levels were at 0 and have been at 0 for some time since I got some problems with my tank sorted. I just did my weekly water change and went through all my test kits, everything is healthy but the ammonia level is high, about 1.5 mg/l. I'm just quite concerned as I've just done a 35-40% water change and the ammonia shouldn't be that high after doing a relatively hefty water change. Do ammonia levels not read right sometimes after adding stress coat as I did the test after adding 10mg of stress coat....I'm clutching at straws really and am quite worried as I've had everything in my tank almost perfect now for 2 months and haven't lost an fish.