This chemical goes by a few different names, but UV Blockout is the chemical that keeps your existing chlorine in the water rather than being evaporated by the sun. Keep your Cyanuric Acid level healthy (30-50ppm) for optimum chlorine-keeping results.
Cyanuric Acid doesn't need to be added too often, we recommend checking and balancing levels once per month.
Warning: Unlike chlorine that dissipates/gets burned up by the Sun's UV rays, cyanuric acid stays in your pool. The only time that cyanuric acid levels reduce is when water is taken out from your pool (in the form of splashes, draining, or backwashing) and is replaced by fresh water. Never add cyanuric acid "in the blind" and always check the level before adding more because once your stabiliser levels are over 50ppm, your chlorine's effectivity goes down.
P.S. If you're using stabilised chlorine or chlorine pucks, we suggest that you closely monitor your cyanuric acid levels to make sure that you don't go over the level. If you're nearing (or at) the maximum level, switch to unstabilised chlorine.
If for any reason your cyanuric acid levels go above the recommended levels then you can consider adding some Bio-Active Cyanuric Acid Reducer to your pool to get the stabiliser level back down. For more information on the Bio-Active, check out our product spotlight here.