How to lower the pH in a pool

As a kid, I always wanted to live in a house with a pool, but I grew up in the middle of nowhere, where ponds were much more likely to be; you know, the kind with tons of algae, sandy bottoms, and murky water. While I don’t yet live in a house with a pool (I live in an apartment in Manhattan), my brother who lives nearby has a pool and a house. He’s also the head of a university’s chemistry department, which comes in handy when doing pool maintenance (who knew pools involved so much chemistry). I have learned that pool owners spend a lot of time balancing pH and alkaline levels.

A high pH in a pool can cause a great deal of discomfort; including cloudy water and algae growth like my childhood ponds, as well as itchy eyes and skin and damage to pool parts.

PH refers to the “potential of hydrogen” of an aqueous solution; in this case: your pool. It measures the acidity of a substance on a scale of 0 to 14. Anything below 7 is considered acidic, while anything above 7 is called “basic.” Chemistry defines a ‘base’ as any aqueous solution of a chemical compound that has a lower concentration of hydrogen than is found in pure water, such as ammonia. They contain ions, can conduct electricity, and feel slippery. Soapy water is an example. Bases and acids are chemical opposites.

To lower the pH in a pool, you need to add more acid. The three acids used as pH reducers include sodium bisulfate (dry acid), muriatic acid, and sulfuric acid.

Both sodium bisulfate and sulfuric acid add sulfates (indicated by their names) to your water that could cause other problems like corrosion of metal parts, degradation of a saltwater generator (if you have one), or damage to concrete . For these reasons, some experts recommend using muriatic acid over the other two.

How to lower the pH of your pool

taste the water

Pool and spa test strips

This test kit contains 100 strips that measure your pool’s Hardness, Chlorine, Bromine, Free Chlorine, pH, Cyanuric Acid and Alkalinity. Simply dip a strip into your pool, remove it and carefully shake off excess water, then compare the colors to the chart on the side of the container.

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