Alkalinity inexplicably up at 13, please help.

[Saltyreef]

Here is something google turned up. Maybe add an 1ML of vinegar?

Step 3: Add Organic Acid Like White Vinegar​

Adding a small dose of white vinegar can be the game-changer when it comes to lowering the alkalinity in the reef tank. It will help to reduce the alkalinity level almost immediately. However, as it also lowers the pH level, you should not use any organic acid like vinegar frequently.

If the pH level drops significantly due to the use of organic acid, here’s what you should do to restore the pH:

• Stir the surface of the tank water. When you agitate the water, the gas exchange will improve in the water. As a result, the oxygenation of the reef tank will increase the pH level will be back to normal again.
• Move the powerheads and return pump outlets towards the water surface.

You could but you would really want to be careful with the vinegar. You would be essentially carbon dosing and risk dropping your nutrients too low or askew.

 

[Jib]

Coral Pro is high to start with.

I'd just let it drop naturally, rather than trying to force it down too fast which will cuase more coral issues.

FWIW, you can use an acid such as muriatic acid or hydrochloric acid to drop Alk, but it cannot be done in tank, and involves dropping the alk on new water before adding to the tank.

I stongly suggest letting it drop naturally

Just saw this, seems along the same line as the vinegar article I found.

Maybe I'll just do big water changes weekly until it comes down...

 

[gbroadbridge]

Here is something google turned up. Maybe add an 1ML of vinegar?

Step 3: Add Organic Acid Like White Vinegar​

Adding a small dose of white vinegar can be the game-changer when it comes to lowering the alkalinity in the reef tank. It will help to reduce the alkalinity level almost immediately. However, as it also lowers the pH level, you should not use any organic acid like vinegar frequently.

If the pH level drops significantly due to the use of organic acid, here’s what you should do to restore the pH:

• Stir the surface of the tank water. When you agitate the water, the gas exchange will improve in the water. As a result, the oxygenation of the reef tank will increase the pH level will be back to normal again.
• Move the powerheads and return pump outlets towards the water surface.

I wouldn't use acetic acid (white vinegar), as it will add acetate and potentially cause a bacterial bloom