Chlorine stabilizer protects chlorine from the degrading effects of sunlight. Reduces chlorine consumption, made of cyanuric acid. Essential for swimming pools utilizing gas chlorine, liquid chlorine (bleach), and calcium hypochlorite tablets or granular for chlorination. 1-1/2 Lb. of chlorine stabilizer per 10,000 gallons of water will raise cyanuric acid level 10 ppm (parts per million).