Limescale may appear in your pool if you have hard water in your area. Hard water is water with a high mineral content. Limescale is actually calcium deposits. Usually, a pool filter and the chemicals in your pool will prevent the formation of deposits in the pool but if the water is neglected they may appear over time. Properly cleaning the pool and keeping the water chemical balance within its proper levels will prevent limescale build up. If you do have limescale however, you will need to clean it away.
Drain the pool of water so that you can enter the inside of the pool.
Remove any debris from the bottom of the pool using a shop vacuum and a pool wall and floor brush.
Prepare a mixture of muriatic acid according to the dilution instructions on the bottle.
Pour the mixture into a spray bottle wearing gloves.
Spray a test area of the liner or tile with your acid to make sure it will not discolour.
Spray the areas with the lime build up with the acid mixture and scrub the area with your brush to remove the scale build up. Rinse the acid as you work to prevent it burning.
Pour soda ash onto the acid to neutralise it. Spray the pool with a garden hose to remove the acid and refill the pool.