My 5 gallon tank constantly has .5ppm of ammonia. I use spring water due to the water quality (1.0 ppm ammonia levels out of tap.) Of course the spring water tests at 0, but before and after water changes I am getting a .5ppm (sometimes the color looks between .25 and .5) reading daily. I use prime on the water due to the ammonia readings. My fish has been in this tank for several weeks now. There are two java ferns and a banana plant as well as a zebra snail. I had my water tested on Saturday and while they were out of the ammonia test, the nitrates and nitrites tested at 0. I had tested the ammonia levels myself (using API liquid test) and had the standard .25-.5ppm reading. On Saturday the lfs (a really nice quality locally owned store with super clean tanks) squeezed one of their filters for me and gave me a bag of it to help seed my tank. I soaked my filter in it and poured it in my tank. I haven't seen any difference in my ammonia readings (I don't have a nitrate or nitrite test.) I have been doing twice a week water changes (around 50% due to the ammonia levels.) Any suggestions on why my ammonia readings are constant?