Right, firstly pH up or down are not fixes for pH problems. When you say you have a pH problem what is the reading. You should avoid adjusting it at all if the range level is 6.4-8.0, axies can reside in this. Don't try for a perfect pH you invariably will cause fluctuations or more problems using the pH up or down powders. If the pH is very low below 6.4 then you can use shell grit in a stocking placed in your tank (shell grit is available from petstores - the stuff used in birdcages).
As for ammonia problem (or nitrites); the solution is spotcleaning daily, don't overfeed (you know if you've overfed if you find any regurgitated food), weekly waterchanges, ensure you test the water weekly and if ammonia or nitrites are above 0, then you do a 20-30% waterchange the same day and test again within 1 or two days.
Waterchanges are what sorts things out. Ammolock or ammonia binders do not work nor fix the problem.
The best freshwater test kits are the test tube variety. You can buy an all in one master test kit that is approximately $50-$70 and includes tests for low and high pH as well as ammonia, nitrite and nitrates. I use the AP (Aquarium Pharmaceutical brand).
The most important one to test for first is ammonia if you can't find the master test kit. Otherwise just make sure you take a sample to the petshop and DON'T buy anything they suggest to fix it - frequent partial (20-30%) waterchanges sort out water quality problems.