muriatic vs. sulfuric

[jaybo500]

Pool store guy said if your pH and Alkalinity are both high you would use muriatic to bring them down. If only pH is high you use sulfuric, as it has little impact on Alkalinity. Any thoughts?

 

[JohnT]

He's wrong. Lowering the pH of the water changes the form of some of the carbonate in the water to carbon dioxide, which reduces the measured alkalinity and makes it possible to remove it from the water by aeration. It doesn't have any permanent effect on the alkalinity unless you aerate the water to remove the CO₂The alkalinity doesn't care how the pH got lower.

Muriatic acid contains hydrogen and chlorine, both of which are normal in a pool. H₂SO₄ leaves sulfur behind.

 

[chem geek]

Muriatic acid contains hydrogen and chlorine, both of which are normal in a pool. H₂SO₄ leaves sulfur behind.

Just for clarity, the "chlorine" in Muriatic Acid is chloride - that is part of salt. The dry acid leaves sulfates behind.