How to use Muriatic Acid to Lower your Pool’s Alkalinity

Is your pool water is a little cloudy or your pool filters may seem to fill with calcium deposits,? Then your pool may be suffering from high alkalinity levels. In this article, were going to learn how to use muriatic acid to lower your pool’s alkalinity.

What is pool water alkalinity?

Alkalinity plays a key role when it comes to pool chemistry, and that’s why it’s necessary to pool maintenance. It refers to dissolved salts, like carbonates, that keep pH stable. If alkalinity is in the right range, pH and chlorine levels are easier to maintain.

To lower alkalinity:

Add muriatic acid. Muriatic acid lowers both pH and alkalinity.

To raise alkalinity:

Add sodium bicarbonate (baking soda). This is different from sodium carbonate (soda ash).

How to Lower Pool Alkalinity

Pool supply stores carry a product called pH Decreaser, which is mostly Sodium Bisulphate. This product will lower both pH and total alkalinity, but you can use muriatic acid instead. Because you may already have it on hand, and it’s cheaper than pH Decreaser. It’s worth knowing the right way to use muriatic acid to lower your pool’s alkalinity.

How to use muriatic acid in your pool water

Muriatic acid balances your pool chemistry by lowering total alkalinity and pH. It has a lower concentration of hydrogen chloride than the muriatic acid you’ll find in stores.

Make sure the chemicals you use have the correct concentration of the functioning agent. Just like the active ingredient in medicine. Achieving balanced water chemistry will be safer. And easier with products formulated especially for use in pools.

If your pool uses a cartridge filter, you may already have muriatic acid on hand. It’s commonly used to deep clean filters. And is especially useful in breaking down the gooey residue that can build up there. If you’ve been using muriatic acid to clean your filter, you can use the same stuff to lower your pool’s alkalinity.


Before you start mixing up chemicals, you need to get your mad scientist gear on. Muriatic acid is extremely caustic. It can burn your skin in seconds. And the vapor from muriatic acid can cause serious respiratory problems.

You’ll need a few things to keep yourself protected when using it like:

Safety goggles
Acid-resistant gloves
Chemical-resistant apron
Plastic bucket
Wooden or plastic stirrer

And for all your pool needs call My Pool Guy for your pool guy!