HCL is a basic requirement of swimming pool maintenance procedure. It essentially lets you maintain the pH balance of your pool. A good pH balance in the pool water ensures that there is no extreme of either acidity or alkalinity. An imbalance in pH could cause eye irritation in swimmers. HCL is also useful for cleaning the tiles and remove the algae in pools.
The pH balance is measured on a scale of 0 to 14. The optimum range of pH for a swimming pool is 7.2 to 7.9. If pH is lower than 7.5, then the water is acidic; if it is higher than 7.5, it is considered alkaline. If the alkalinity of the water in the pool increases, you add a certain quantity of HCL to bring it down to the optimum range. An essential piece of equipment for maintaining your pool is a pH test kit, which you can find at any pool supply store.
Always remember that you should add acid to water and not the other way around. Also, pour acid in the deeper end of the pool and make sure that the filtration pump is turned on. If you are using HCL to clean pool tiles, pour a few drops on the tile using a narrow-nozzle bottle and rub the tiles with a plastic brush to clean them. Wear gloves and goggles to avoid accidentally getting the acid on your skin or in your eyes.
The quantity of acid needed is directly proportional to the size of your pool. For example, for a 5,000-gallon pool, 6 oz. of HCL will be sufficient. See Resources for a link to a chart that shows you the correct amount for your size pool.
HCL is a very strong acid and can easily stain or burn your skin. It should be kept in a safe place at all times and away from the reach of children. Always use only the prescribed amount of HCL for treating pool water.