Yes....that's right....for fish. Don't use ph ADJUSTERS for aquariums though.....only the ph testers. (fish adjusters havee too much salt)

The ph of your water AND soil runoff should be between 6.2-6.8. If the ph of your runoff is abnormal I would not use anything but plain, ph correct tap water until you feel the problem is resolved.

PS..in a pinch you can use distilled white vinegar to lower ph and baking soda to raise it.