According to Pool Center, pH is a measurement of acidity. The lower the pH measures in pool water, the more acidic it will be. A pH is neutral at 7. Pool water pH should be between 7.2 and 7.5 because this correlates with the pH of the human eye. If the pH value of pool water is too low, the water has higher acidity and can cause a number of problems.

Pool water pH should be close to neutral.

Destruction of Pool Walls and Floor

If pH is too high in a pool, damage can occur to the pool walls, floor and accessories. The high acidity of the water dissolves plaster and grout of a pool, making surfaces rough. Water with low pH will corrode metal products, wearing away at metal ladders and heating pumps. Low pH in a pool can also destroy any pool toys or flotation devices coming into contact with the water.

Cleanliness Issues

Water in a pool with low pH will be discolored. It may be cloudy from the wearing away of tile or have a dark and murky color from the corrosion of metal. A pool with low pH will not have a clean sparkle and shine. Chlorine dissipates quickly in water with low pH, and Pool Wizard states five times more chlorine would need to be added to an acidic pool for the water to be disinfected.

Skin and Eye Irritation

Swimmers exposed to a pool with low pH will experience unpleasant effects. The high acidity of pools with a pH lower than 7 can cause eyes and nose to have a burning sensation. The skin and scalp of an individual swimming in a pool with low pH will become dry, itchy and possibly even develop a rash.


The effects of low pH on the walls and metals within a pool release sulphates into the water. When the sulfates come into contact with the walls and the floor of the pool, dark brown and black stains will appear on the walls and the floors of the pool.