Swimming pools have many problems. The biggest problem is the diseases that are transmitted to people from swimming pools. To prevent this problem, chlorine is widely used in swimming pools. Chlorine is used for disinfection of the pool water. Chlorine added for the disinfection of the pool water also necessitates the use of other chemicals. The second most important parameter after chlorination is the pH value of the pool water. The pH range of the pool water should be between 7.2 and 7.8. Strong acid (HCl) or strong base (NaOH) is added to achieve the pH range of the pool water. If the pH value of the pool water exceeds 7.8, the chlorine disinfection feature does not exist. Even if all parameters are provided, chlorine is completely ineffective on cryptosporodium, hepatitis, mosses, algaes, fungis and more. Out of all of them, Cyanuric acid is added so that the chlorine is less affected by sunlight. In addition, other chemicals are added for other reasons. Our group has developed a number of technologies to eliminate the use of chemicals in swimming pools. Finally, oxygen nano-bubbles in the pool water is relaxing, healthy and refreshing. So that you can place no-chemical flag on your pool.