Ammonia & nitrite should always be 0 in a cycled tank. You want to keep nitrates as low as possible, 40 ppm or less, the less the better. PH is something you really don't want to play with, choose your fish according to your pH. Adjusting your pH with chemicals is usually a bad idea, unless you are reconstituting ro water. Very few freshwater fish require this, most can be acclimated to your water pH & hardness.