Alternatives to Muriatic Acid for Swimming Pools
You can avoid handling liquid muriatic acid in maintaining the chemical balance in your swimming pool by choosing pool sanitizers that don't raise the pool's pH or by using other products to lower a high pH. Muriatic acid, a form of hydrochloric acid, can be dangerous if accidentally spilled or splashed and because of its fumes.
Sodium dichlor is a granular or tablet form of chlorine sanitizer with a pH range of 6.8 to 7.0, nearly neutral. Ideal pH for a pool is between 7.2 and 7.6, so dichlor will not raise pH. The recommended way to add the granular form is to mix it in a five-gallon bucket to dissolve it and walk it around the pool, pouring it as you go. Use the tablets in an erosion type feeder, either a floating feeder in the pool or a tablet chlorinator attached to the pool plumbing.
Trichlor tablets are also effective in reducing or eliminating the need for muriatic acid. Because it has a very low pH (2.8 to 3.0), it's unlikely you will need any muriatic acid at all. Instead, you may occasionally need to increase the pH by adding soda ash or baking soda to the water. Most trichlor also contains cyanuric acid, a stabilizing agent that acts as a blocker of ultraviolet rays that break down chlorine. Use trichlor in a floating feeder or a tablet chlorinator attached to the pool plumbing. Never put trichlor tablets into the pool skimmer. The low pH will react with the metal parts in the equipment and damage them.
Sodium bisulfate, sometimes called dry acid, is another way to lower pH without using liquid muriatic acid. Unlike sodium dichlor and trichlor, it is not a sanitizer. It comes in crystal form that looks like small granules. It readily dissolves in water so you can add it directly to the deep end of the pool if you spread it out over the surface. Several commercial versions are available, such as pH Reducer. It eliminates the problem of fumes as long as you keep it dry before using it. It is also less subject to spills and splashes. Keep it in a closed container and handle it with care because it is acidic.