pH 7.9 Alk 14?

[lowman31]

What would cause my pH to be uneffected by addition of NaHCO3? I noticed my pH was low today so I added some of my part B solution as I normally do. This time it did not work and my pH is staying at 7.9. I recalibrated my probe and the findings were the same. I tested my Alk and it was high: 14. Any suggestions would be appreciated?

Jim

[lowman31]

Just wanted to add that these measurements were taken during the day, I don't have a calcium reactor, and my windows are open. Thank you for any suggestions.

[Percula9]

A pH of 7.9 is okay. Try measuring your pH in a glass of water away from the tank. Let the alk come down to at least 9-10dkh. Once that happens use sodium carbonate to raise pH. Bicarbonate doesn't change pH that much. Initially it will lower it,until bicarbonate and carbonate come back into equilibrium. When bicarbonate dissociates in water the hydrogen ion is released which lowers pH.

[lowman31]

Thanks percula9. I know pH 7.9 is okay, I just know it is going to drop over night. What would cause my situation?

[lowman31]

Thanks percula9. I know pH 7.9 is okay, I just know it is going to drop over night. What would cause my situation?

[Percula9]

The pH drops at night because algae that performs photosynthesis produce CO2 instead of consuming it. The CO2 lowers pH by producing carbonic acid. Try more aeration with fresh air.

[lowman31]

Thank you. The other thing I want to know is what can cause the pH to be uneffeted by addition of NaHCO3 and limewater?

[feel-os25at]

Hello
Values are the same between morning and evening ? 7.9 is low. Lighting ? 14 alk is high.
Do you often water changes?

[Percula9]

The addition of sodium bicarbonate doesn't affect pH because of the release of the hydrogen ion from the dissociation of the bicarbonate. The lime water may not be saturated or your not adding enough.

[lowman31]

That makes sense. My pH is normalized today. I wish I knew what event took place yesterday to cause the acute drop in pH. Thanks percula9.