When you test for pH (or any other chemical parameter for that matter), it is good to have a ball park idea of what it may be, before testing, and a good idea to know if you are doing the test correctly, and if your materials are clean and accurate.
When testing pH for water that is expected to be 7 or "lower", you use low range reagents.
If your water is basic, higher than 7, you match with a known standard for high range.
For low, you need "known standards" of probably be 4 and a 7.
When testing "basic" pH water, your known standard is usually a 7 and a 10.
If you test your standards, and they match your test readings, then you've done your test correctly, and your reagents for testing are within range.
If you test your 7 standard, and it reads 8.2, something is wrong, could be your reagents are old, could be your test tubes are dirty (contaminated), could be your simply screwing it up.
If you live in a hard water, high pH area, it's probably not a good idea to keep Uaru ferandezeyepezi, or some other wild soft water type.
If you live in a soft water area, rift lake or wild Central Americans aren't a good idea.
If the fish you want are bred in your area, then fooling around trying to change your pH is an exercise futility, because it doesn't matter.
Simply doing frequent water changes to keep from having drastic pH swings, is much more important than matching some idealistic number.