My water, which contains chloramines, tests about 1 ppm ammonia. If I do a 50% water change, my tank will show about .5 ppm ammonia after a change. If I did a 20% change, I'd have about .2 ppm ammonia, but I'm not sure most hobby tests are sufficiently sensitive to reliably measure that little. Also, if you have a healthy biofilter, that ammonia will soon be taken up. Some people don't like exposing their fish to ANY ammonia unnecessarily and they use something that not only breaks the chlorine-ammonia bond, but also detoxes the ammonia. StressCoat does the former, but not the latter. (So does my bottle of generic sodium thiosulphate, which costs a fraction of what StressCoat does, and doesn't coat my fishes' gills and other sensitive tissues with "soothing" aloe.)
On my tanks at work, I regularly do 80% changes; I think using something like Amquel is cheap insurance against long term effects of regularly exposing my fish to low levels of ammonia.
If your water has only chlorine, but not chloramines, then a simple dechlorinator like StressCoat is sufficient.
HTH,
Jim
On my tanks at work, I regularly do 80% changes; I think using something like Amquel is cheap insurance against long term effects of regularly exposing my fish to low levels of ammonia.
If your water has only chlorine, but not chloramines, then a simple dechlorinator like StressCoat is sufficient.
HTH,
Jim