If you use acid for cleaning cement hydrochloric or mercuric acid is generally used However you may be better of trying to clean it using only a pressure sprayer first.
cleaning pools
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Cleaning swimming pools, cleaning drinking water and chlorine is used in bleaches as well.
Hydrochloric acid
chlorine itself has very little effect on the plaster coating that is used in most pools, if your coating is of a color , chlorine added directly to a spot may cause some discoloration , but unlikely, the pH or alkalinity of the water is of much more concern than the chlorine when it comes to a gunite pool coating.
Here are a couple: http://www.reedpumps.com/ http://www.shotcretetechnologies.com/ http://www.monolithic.com/construction/shotcrete_gunite/ Hope this helps ...
Hydrochloric acid is most commonly known as muriatic acid and is used to lower pH in pools
its concentrated sulphuric acid
Muriatic acid
Chlorine.
You can add dry acid to your pool when your pH is above 7.8
Bleach & Chlorine also Muriatic for swimming pools. Hydrochloric acid is usedin digestion of food in human body.