Hydrochloric Acid

Also known as muriatic acid, hydrochloric acid is used to lower the total alkalinity (or pH) of pool water.  It can also be used to ‘acid wash’ an empty pool.

If pool water becomes cloudy, and an acid demand test has been run, showing that the pH of a swimming pool is too high, hydrochloric acid will need to be added to the pool water to lower the total alkalinity.  It is recommended that hydrochloric acid be handled very carefully and added to the deep end of the swimming pool, taking care not to allow the acid to get near the walls or fittings of the pool.  If hydrochloric acid (or any other chemical for that matter) must be diluted, remember the safety recommendation of adding acid to the water, not by adding water to the acid.  Hydrochloric acid can also be used if a swimming pool needs to be acid washed.  Using hydrochloric acid will remove a thin layer of plaster from the interior of an emptied pool.  Acid washing with hydrochloric acid should be left to professionals preferably, as it can be a dangerous acid if not handled knowledgably.