What pH Should a Pool Be?

Ideally, the pH of a pool should be between 7.0 and 7.8. If the pH falls below 7.0, the water will become too acidic for the swimmers and may sting their eyes, making it necessary to raise the pH in the pool. 

Similarly, if the pH exceeds 7.8, the water will become too alkaline. It may turn too cloudy and result in white- or gray-colored deposits on the pool surface or equipment. 

In this post, we’ll do a deep dive into what could happen in case of pH imbalance and what can you do to avoid it.

Why Is It Necessary to Maintain a Normal Pool pH?

pH imbalance is a severe health hazard. If you consistently swim in a pool with an extremely low or high pH, you might develop chronic illnesses, such as asthma.

By definition, the pH of a pool refers to how acidic or alkaline the water is. Considering the standard pH scale, 7.0 represents neutrality. If the water has a pH of 7, it is pure and typically harmless. This is why the most ideal pH for pools ranges from 7.0 to 7.8.

However, as we go down on the pH scale (below 7.0), the acidity continues to increase. The maximum acceptable drop in pH is about 6.9 to 7.0. If the pH drops even further and you continue to swim, the water can:

  • Dry out and damage the quality of your skin and hair–it may even lead to a skin condition called dermatitis
  • Cause itching and burning in your skin and eyes
  • Lead to coughing, wheezing, and shortness of breath
  • Damage tooth enamel and lead to tooth decay

As for alkalinity, it increases as we go up the pH scale. Given that, the maximum acceptable alkalinity of pool water is about 8.5. Beyond this, the alkaline water can cause skin and eye irritation. High alkalinity also reduces the effectiveness of chlorine, which may lead to waterborne illnesses.

In addition, an abnormally high pH can damage the pool itself in the following ways:

  • Scaling: Alkaline water leads to the formation of whitish or grayish deposits on the pool’s surface or equipment.
  • Staining: If the water is highly alkaline and also has high quantities of iron and other minerals, it can stain the pool’s surface.
  • Algae growth: Algae grows rapidly in alkaline water. This makes the water green, unsightly, and of course, unhygienic for swimming.
  • Reduced lifespan of pool equipment: Alkaline water can corrode the pumps, filters, and heaters installed in the pool, thus reducing their lifespan.

Keep in mind that the true impact of pH imbalance on both human health and the swimming pool depends on the severity of the imbalance and its duration. 

Three Ways to Control Pool pH

Now, let’s check out three quick ways of restoring pool pH:

  1. Lower With Muriatic Acid

First, calculate the amount of muriatic or hydrochloric acid required according to the current pH and volume of your pool. Next, carefully add the acid to the pool in a well-ventilated area. Once done, allow the water to circulate for a few hours. Then, retest the pH and adjust further if needed.

  1. Increase With Soda Ash

If the water is acidic, increase the pH with soda ash or sodium carbonate. First, dilute the required amount of soda ash in a bucket of water. Then, gradually add the solution to the pool water. Leave it for a few hours, then retest before swimming. 

  1. Shock the Pool

Shocking a pool refers to sanitizing it with chlorine or other oxidizing agents (and it leads to a slight increase in pH). It helps kill bacteria and contaminants, and inhibits the growth of algae. Although this process is recommended for every pool on a bi-weekly basis, it’s not a great way to control pool pH. 

Final Thoughts

Pool pH should ideally be between 7.0 and 7.8. Anything out of this range can harm not only the swimmers but also the pool itself.

For more helpful information like this, be sure to check out our posts on what pH does for a pool and how to raise the pH in well water!

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