Check the pH once a day.
The pH is linked the health of the fish, the creation of bacteria in the system, and the ability of plants to absorb nutrients. The pH range for freshwater African catfish is between 5.0 and 7.0 – slightly acidic. If the pH is outside that range it is harmful or even deadly for the fish. For that reason we try to maintain the pH between 6.0 and maximum 7.0. By checking the pH we can see which nutrients need to be added. Potassium sulfate is added to decrease the pH and potassium hydroxide to increase it.
1. Take a water sample from the input to tank 5.
2. Turn on the pH meter and plunge the probe in the sample water. There is a small clock logo on the screen, indicating that the probe is measuring. When that clock disappears write down the value.
3. Store the pH meter upright, as the cap is filled with a calibration solution. Make sure there is solution left in the cap.
4. Adjust the potassium sulfate and/or potassium hydroxyde quantities for the day accordingly.