Thank you Anna. I guess I'm just a nervous fish keeper who still considers herself a novice. I use the API Master Test Kit which measures the PH from 6.0 - 7.6. Are there other products that measure lower PH?
The one you have is the standard one. However, there are test kits for measuring water pH that aren't specifically for fish tanks. There's no reason you can't use these, since the chemicals never have contact with the fish. This one measures pH from 3.5 to 10.5: