When adjusting pH, it can take dosing once a day for several days in a row, particularly if your water is hard also. One dose will not adjust it at all in most cases. You need to dose, wait 24 hours, test, re-dose if it has not dropped, wait another 24 hours, re-test, and re-dose, etc. It also depends on the cause of the high pH. Is it the water source or do you have some large natural rock in the tank that buffers it up? Adding driftwood to the tank will help lower the pH naturally, over time.
Date published: 2017-09-14