Are you testing for nitrites, has it spiked yet or even shown up? That will let you know where you are in your cycle. Also what is the ph of the water. Is this the tank you were saying that the ph was low on? If that is the case, a ph of 6 is a good thing, ammonia is less toxic at an acidic ph. Watch the fish closely, as long as they are not gasping at the surface or "gilling" rapidly you are probably ok. Also look at their gills for redness etc. Cut back your feedings to almost nothing, everyother day at the most, until your cycle finishes. The nitrite end of the cycle is faster than the ammonia part. Once nitrites appear the bacteria is starting to convert the ammonia and the cycle will speed up. It still takes about 4-6 weeks to cycle a tank. So you really don't have an ammonia problem you have a cycle starting and this is normal, so be patient. Don't get carried away with changing filter media at this stage or you will slow the cycle down. When doing water changes, vacuum up the poop, but don't try and clean all the gravel or you will slow the cycle down.
Fishkeeping teaches patience. *twirlysmiley*