I will explain here what the hydrochloric acid is used for in the swimming pool: by descaling and the dosage to lower the TAC and the pH.
Hydrochloric acid is a dangerous chemical compound. It should be handled with care, especially gloves and protective glasses. For the treatment of the swimming pool, one can often use other products, less dangerous.
To use it, it must be diluted in a large volume of water: 30% acid and 70% water. Always pour the acid into the water and never the other way around.
Hydrochloric acid is corrosive to metals. So the pool pump and other equipment are not going to like it at all.
After putting hydrochloric acid in the pool. you should avoid bathing for 24 to 48 hours.
For the maintenance of the swimming pool, hydrochloric acid can be useful for 3 reasons:
The hydrochloric acid allows to lower the pH of the swimming pool, strongly. The dosage of hydrochloric acid in the swimming pool is approximately 10mL per m³ to lower the pH by 0.3. It is very powerful!
For comparison, pH-lowering products containing sodium bisulfate or sulfuric acid have a potency of about 0.15 per 10mL per m³.
Like any product that lowers the pH, hydrochloric acid also lowers the TAC. Compared to products lowering the pH, hydrochloric acid will have an even greater impact on the TAC. Moreover, the dosages to be carried out depend on the TAC of the swimming pool: the higher the TAC, the more chemical product is required.
Hydrochloric acid helps to lower the TAC of the pool. It is even very effective in this area. The hydrochloric acid dosage is approximately 2mL per m³ to lower the pool’s TAC by 1 ppm (0.1 ° F).
Hydrochloric acid dissolves limestone. It is sometimes used for very scaled toilets.
In a swimming pool where the water is particularly hard, limestone can form on the walls and at the bottom. To prevent this problem, there are lime sequestering agents. To correct the problem, one can use hydrochloric acid.
If the pool is very calcified, then empty the pool and spray hydrochloric acid on the walls, little by little, then wipe with a sponge.
I also recommend putting hydrochloric acid 40cm away from the coping, leaving it to stand overnight and then turning on the filtration for 48 hours, without swimming.
