After you kill all the algae, the dead algae will still be in the water. It then takes the filter a while (from a day to a week) to filter it all out. You should see a visible improvement each day.
The PH will tend to read higher than it actually is when the FC level is high (> 10). So don't lower the PH too much until you get a PH reading at a lower FC level.
The PH will tend to read higher than it actually is when the FC level is high (> 10). So don't lower the PH too much until you get a PH reading at a lower FC level.