The main condition for keeping a certain level of hygene in a swimming pool is to make regular chemical tests and depending on the results, to use the necessary chemicals in order to reach the optimum level of chemical-mineral. It is compulsory to test the parameters such as pH, free chlorine, total alkalinity, calcium hardness, ammonia and stabilisator level. The mostly used measure in a pool is free chlorine pH measure. The ideal PH value is between 7,2-7,4. Under the Poolline brand, there are liquid or tablet test kits. Depending on the type of the kits, a measurement plan is made. In individual swimming pools, once a day, in public swimming pools at least three times a day free chlorine–pH must be measured. Other chemical and mineral measures must also be made considering the type of the pool the number of users.