Hi all,
Bob is right about the results, it may be the test kit, but you need the ammonia and nitrite to read 0ppm.
The liquid test kits are best, but with a couple of provisos. The tests are only really suitable for measuring ammonia during cycling,
ammonia is toxic at very low levels that the test kit cannot measure. Actually even with lab grade ion selective electrodes it is very difficult to measure ammonia meaningfully, and if you are a scientist interested in water quality you would use a combination of 4 day BOD and a biotic index.
The other issue is that a water conditioner like "Prime" or "Amquel" will bind the ammonia and de-activate it, but it will still measure on the test kit. The final factor is the NH3 / NH4+, pH, temperature relationship, which means why we measure TAN (Total Ammonia Nitrogen), the ammonia molecule (NH3) is much more toxic than the ammonium ion (NH4+) and warm water much more dangerous than cold, details here: <
http://www.fishdoc.co.uk/water/ammonia.html>. The practical application of this is that if you keep
Tropheus etc. you have to be very good at water management.
Fish are producing ammonia all the time from their gills, but if you suspect that traces of ammonia are remaining in your tank, you need to act immediately. I'll assume that you are not grossly over-stocked, so there are 2 major possibilities for the ammonia source, either from the persistent "chloramine" in the tap water, or from a failure of the biological filtration with-in the filter.
If it is a chloramine problem, in the short term you can use a water conditioner, in the longer term you need another water source (or HMA/RO filtration). Active plant growth will also work.
Filter issues
Even if you have a large capacity canister filter, if the water is de-oxygenated in the filter ammonia will pass through the filter without being converted to nitrite and nitrate. This can happen particularly if you have a lot of fine sponge or filter wadding in your filter.
cheers Darrel
ive spoken to Jo and it's all sorted