A Calcite Water Neutralizer Can Treat Acid Waters From pH 5.0 up to pH 6.9.
A calcite water neutralizer will work best for treating acid well water if the pH of the water is between 5 and 6.9. Over 6.9 no neutralizer is needed.
For pH levels below 5.0, we generally recommend a chemical feed pump injecting soda ash for residential applications, or sodium hydroxide for commercial and industrial applications.
When To Use 100% Calcite
Use 100% calcite if the pH is from 6.0 up to 6.9. Calcite is a safe, easy to use, natural product made from high purity limestone. It is specially selected and sized to optimally adjust pH in potable water systems. Having used various brands over many years, the one we like the best is Puri-Cal. It is mined in Washington state and NSF certified for drinking water. It is clean, white and dissolves readily, unlike some types we used in the past.
However, if the pH is less than 6.0 then it works better if you blend or add some magnesium oxide (“Mag Oxide”) to it.
Mag oxide is sold under various brand names such as Corosex, Flomag, and other names. It is also a natural product made from mineral sources. If you use too much Mag Oxide in the blend, it can raise the pH too high. A mixture of about 80% or 90% calcite to 20% to 10% magnesium oxide works well.
Hard Water Can Be a Problem
Calcite dissolves more easily and rapidly if the water isn’t very high in hardness. If the water already has a high level of hardness in it, then the calcite won’t dissolve properly. Generally, this is not a big problem because typically acidic water is also naturally soft water.
However, if the water is over 10 grains per gallon (or about 171 mg/L) then it is best to use a chemical feed pump and inject a soda ash solution and not use a calcite or mag oxide blend system.