Originally Posted by alidawn15
Am I correct in thinking that the ammonia test doesn't matter unless it goes over .5?
To answer this, I will back up a bit, so there is no misunderstanding by other members who may be reading this and jumping to the wrong conclusion.
Ammonia and nitrite should never read above zero in a cycled and established aquarium. However, when ammonia (or nitrite) is entering the system via water changes, that is a temporary influx of whichever and this should be handled by a suitable water conditioner. Provided the influx of ammonia/nitrite is relatively minimal, the system (through the plants and/or bacteria) will catch up by the time the conditioner has lost its ability to detoxify [usually 24 hours].
A couple days after the water change a test should indicate zero ammonia (or nitrite) because by then the slight influx would have been handled by the plants/bacteria. If not, there would seem to be a source within the aquarium, and this should be investigated.
With respect to your test, if the reading indicates ammonia above 0 you must consider the probabilities: taken the same day as the water change should mean the "ammonia" is ammonium, so no issue. Taken 2 days later, it may mean problems.