When and How to Add Stabilizer to a Pool

Whether managing a commercial or public swimming pool, or one in a backyard, knowing when to add stabilizer to a pool is vital in keeping the water clean and the pool healthy and free of pathogens. What is a pool stabilizer? It is often referred to by several names—chlorine stabilizer, pool conditioner, chlorine pool stabilizer, among others—but basically, it is a chemical additive that functions to stabilize and extend the active life of the chlorine in the pool water.

What is a Pool Stabilizer?

Pool stabilizers are important to maintain a clean swimming pool. Along with other factors for keeping a swimming pool clean, like pH, total alkalinity, and water hardness, pool stabilizers need to be adequately regulated and tested. They are derived from a chemical compound called cyanuric acid (CYA), and come in several forms—granular or liquid, or in chlorine tablets (or sticks) called trichlor, or shock, called dichlor. When chlorine and cyanuric acid are combined in shock or tablet form, it is referred to as stabilized chlorine.

The addition of a cyanuric acid stabilizer to pool waters treated with chlorine is necessary to protect the active life of chlorine and its derivatives in the waters from the damaging effects of the sun’s ultraviolet (UV) rays. When exposed to UV rays, chlorine evaporates rapidly. Therefore, CYA specifically acts to inhibit the degradation of chlorine in the water caused by sunlight. Without it, within two hours chlorine is reduced by as much as 95 percent in the shallow areas and to 75 percent in waters up to 4.5 feet. Percentages can vary depending on pH and water temperature, but the rapid decomposition of chlorine will occur nonetheless, and with it, the health of your pool’s water.

Cyanuric acid’s effectiveness works by chemically bonding to the chlorine ions when introduced in the pool water. That attachment protects the chlorine from damage by the sun’s UV rays. When the proper amount of CYA is added to pool water, it slows the rate in which chlorine is released, extending its active life, and reducing further chemical needs and costs.

Think of CYA as sunscreen for the chlorine in the swimming pool. In order to protect chlorine loss and improve its active life, the water must be conditioned with a CYA pool stabilizer. On the other hand, it is important that the proper amount is added. Ideally, the level of cyanuric acid in a pool should be 30 ppm, and no higher than 50 ppm. Anything below 30 ppm is ineffective, with higher rates of chlorine evaporation. Anything above 50 ppm the stabilization effect of CYA starts to level off. Too much CYA in pool water will interfere with the chlorine’s ability to kill bacteria and algae from forming.

When to Add Stabilizer to a Pool

Before adding pool stabilizer to a swimming pool, the water should be tested to ensure the correct dosage is added, or if any amount is required. Unlike chlorine, CYA does not evaporate. It remains in the pool water until it is either splashed out, backwashed, or drained. It can also be diluted when water is added or after heavy rains.

Pools open year-round should test the CYA concentration levels in the water at regular intervals. Those opened in the springtime should be tested only after the pool filter has been on and circulating the water for about three to five days. This is because cyanuric acid is denser than water, and without the filter on and water circulating, it sinks and settles on the bottom of the pool. Either-or, it’s likely that any significant addition of CYA to the water will be determined by whether it is a public or private pool, with the former requiring more monitoring. Keep in mind, if using stabilized chlorine each week, trichlor tablets or dichlor shock, that CYA is added with each application.

How to Add Stabilizer

Knowing how to add stabilizer to a pool is just as important as knowing when. To achieve the recommended amount of 30 ppm, add one pound of CYA stabilizer per 4,000 gallons of water. The chemical is a strong acid so wearing gloves and goggles when preparing the solution is well-advised. Once the required amount of stabilizer has been calculated, mix it in a five-gallon bucket of warm water. Once the solution is prepared it can be evenly distributed around the inside edges of the pool.

Adding a CYA pool stabilizer is important to keep your swimming pool water clean and healthy. The water should be tested regularly to make sure it has the ideal CYA level and no CYA stabilizer should be added until the water is tested.

If you have additional questions about when to add stabilizer to a pool, please contact our experienced team at Halogen Supply today!