The first thing to do is vacuum the gravel and change out 25% of the water. This should always be the first recourse when something is off in the tank. Then wait several hours and re-test the water quality, but don't stop at pH. Test ammonia, nitrite, nitrate, and alkalinity to get a complete picture. Also, test the tap water you are using for a comparison. If your pH is low because the tank is long overdue for a water change, for example, you want to do several small, partial water changes over a couple of weeks first, to get the tank balanced, before deciding to use a chemical to increase the pH. Once it is balanced again, if you still need the Correct pH because the tap water is keeping the pH low, then it would be 4.5 to 5 tablets each time you dose. How often will depend on how quickly it works, and how long it will last, and that varies due to the types of fish, number of fish, how often you do water changes, and so forth. Always test regularly, allowing a day in between any treatments.
Date published: 2018-08-06