The only definite way to remove cyanuric acid from a pool is to drain and replace the existing water and then use a chlorine treatment with a lower amount of cyanuric acid conditioner. If draining and refilling a pool is undesirable or impossible, some companies offer products that attempt to reduce the amount of cyanuric acid in a pool. Because these products use microorganisms as their active ingredients however, their results can vary.
In chlorine-treated pools, some cyanuric acid is actually desirable. Cyanuric acid protects chlorine molecules from being broken down by the sun's ultraviolet rays. However, when a pool contains too much cyanuric acid, chlorine molecules bond with cyanuric acid molecules, making the chlorine ineffective. Because cyanuric acid is stable at most temperatures and does not get broken down by the sun, removing excess cyanuric acid is difficult.
Cyanuric acid removers work by introducing beneficial microorganisms into the pool. These microbes break down cyanuric acid molecules in a process that provides them with energy. However, microorganism-based cyanuric acid removers are not always effective, particularly at low temperatures.
Cyanuric acid is only a problem in types of chlorine treatments that require an ultraviolet stabilizer. Avoiding the cyanuric acid issue entirely is possible by using a type of chlorine that does not need stabilization, such as calcium hypochlorite or sodium hypochlorite.