Pool Care Basics

How to Sanitize, Test, and Balance Your Swimming Pool Water

Along with endless hours of fun with family and friends, owning a swimming pool also brings with it the need for regular upkeep. Maintaining a clean pool is essential to the health of swimmers and will preserve the beauty and function of the structure. Learn how to treat your so you and your family can enjoy swimming all season long.


Sanitize the Water 

Proper water care is one of the most important parts of maintaining your pool. Over time, organic contaminants such as sweat, lotion, and other germs build up in the pool. Treating your pool with sanitizers destroys the organic matter and prevents the growth of bacteria and algae, keeping the water clean and safe to swim in.

Chlorine is the most widely used and highly effective sanitizer and oxidizer. It can be added to a pool in the form of granules (dichlor) or tablets and sticks (trichlor), which are used in floating chemical feeders or filter baskets. Chlorine also functions as a shock when used in large doses of 10 ppm; you may need to shock (superchlorinate) your pool when there is a major drop in stabilizer levels or if you see algae growth.

Some pool owners have been converting to saltwater sanitizing systems, which eliminate the need to add chlorine by hand. Instead, several pounds of salt (sodium chloride) are added to the pool, and as the water (and dissolved salt) passes through the system, a chlorine generator containing a catalytic cell converts the salt to chlorine. Once the water is sanitized, the chlorine reverts back to sodium chloride. Since most of the water contains saline, it becomes smooth to the touch.

There are also non-chlorine stabilizers like bromine and biguanide, which are gentler on the skin and eyes and make the water feel silky smooth. Bromine is generally used more in spas and hot tubs rather than pools because it is more stable in high temperatures and is effective at higher pH levels. Also, because it burns off easily in sunlight, it is better kept in hot tubs since they remain covered when not in use.

Biguanide is often sold as a set (a sanitizer, shock, and clarifier) because it cannot be combined with chlorine, bromine, or mineral sanitizers. Biguanide pools also must be oxidized with hydrogen peroxide because they are incompatible with monopersulfate and chlorine shock. Biguanide is more expensive than chlorine or bromine, but steadier in sunlight than bromine. Biguanide’s benefit over chlorine is that it will not dry or irritate skin or fade swimwear.

Supplemental sanitizers, including mineral systems, ionizers, and ozonators can be utilized to reduce the use of a chemical sanitizer. Mineral sanitizer systems (mineral purifiers) and mineral ionizers consist of sticks or cartridges that slide into a pool’s or spa’s cartridge filter and release metals (typically a combination of silver, copper, and zinc) into the water, which helps sanitize the water and control algae. Mineral systems can leave skin feeling softer than water containing chlorine alone.

Ozonators (ozone generators) release ozone, a short-acting oxidizer, into the water. They are commonly used on hot tubs and come built-in on many models. They are less common in pools, but some systems are available from several companies.

Balance the Water 

Balanced pool water ensures the efficiency of your sanitizer and prevents scale from forming on the pool’s surface and equipment. Bacteria continuously enter the pool from many sources, so it’s important to monitor or check the chemical levels in your pool on a regular basis.

Most pool owners use test strips or liquid kits to examine their pool’s water chemistry. Test strips are dipped or swirled in the water for a few seconds and then removed. After waiting the advised number of seconds, users compare the colors on the test strip to the color comparator on the bottle to read the levels of chlorine, bromine, pH, etc. in the water.

Liquid test kits require users to put a sample of water into a plastic comparator and add drops of chemical reagents (substances that react with dissolved chemicals and elements to change the water’s color) to determine the parameter levels.

Newer testing methods have become available in the past few years including digital test strip readers, electronic floating sensors, and even an app. Digital test strip readers provide numerical results without color comparisons. Following the manufacturer’s instructions, users simply dip the strip into the water and then insert it into the reader to see the levels of chlorine, pH, and total alkalinity.

Electronic floating sensors evaluate the water’s chemical levels and display the results on an indoor monitor. The device also displays the water temperature and advises proper amounts of chemicals to add when the levels are out of balance.

Pool owners with an iPhone or Android phone can download an app and check the chemistry levels right on their phone. After dipping the corresponding test trip in the water, take a picture of it with your smartphone; the app will then display results and recommendations right on the screen. It also keeps a history of your chemistry results for easy reference.

Photo courtesy of Mission Valley Pools & Spas, Inc.

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