Understanding Pool Chemistry

For many people, the word “chemistry” conjures images of mad scientists and complicated equations. When it comes to pool chemistry, though, it need not be a scary topic! As long as you have a basic understanding of your pool and what it needs, keeping the water properly balanced may not be as difficult as you imagine. Here, we take a dive into the fundamentals of water chemistry, balancing pH levels, sanitization methods, and the importance of regular maintenance for pristine pool water.

Three Elements to Understand

To begin with, let’s discuss the basics of pool chemistry. You have no doubt heard the term “balanced” applied to pool water, but what does that mean, and why does it matter? Chemically balancing your pool water keeps it safe for swimming, as well as protecting the pool surface and equipment. The chemistry of the pool can be thrown off by several things, but the main thing you need to understand is the elements involved in keeping it balanced.

1. pH: This is the measure of how acidic or alkaline your pool water is, and it is the most important factor in balancing the water. If the pH is too low, it can be corrosive and burn your eyes. If it is too high, on the other hand, scaling and calcium buildup may affect your pool and equipment. We will look at pH more closely in a moment, but for now, the point to note is that the ideal pH for a pool is between 7.4 and 7.6.
2. Total Alkalinity: When you measure alkalinity, you are determining the amount of carbonates and hydroxides in the water. The reason you want to know this information is that these chemicals help control and moderate the pH. The total alkalinity of your pool water should be between 60 and 200 parts per million (ppm).
3. Calcium Hardness: Why do you care how much calcium is in your pool? If the water has too much calcium, it can become unstable and cloudy. If it has too little calcium, the water can cause staining and damage metal fixtures in your pool. Dissolved calcium in your pool should be in the range of 80 to 500 ppm.

The Basics of pH

Since pH is such an important factor in keeping your pool water clear, let’s look at it a little more closely, so that you can better understand the concept of pH. First, what does pH mean? It refers to the potential of hydrogen, which refers to the amount of hydrogen atoms in the water, and it is measured on a scale from 0 to 14. Pure water is right in the middle, at a 7, with anything below seven being acidic, and anything higher than 7 being alkaline, or basic. Water with high acidity is not pleasant for swimming or for the pool itself. It can dry out your skin, burn your eyes, and damage your pool’s pipes and filter system. When the alkalinity is too high, you risk a rash by swimming in it, and it can cause damaging scale to build up in your pool. Additionally, your pool’s sanitizers, especially chlorine, need the right pH to work properly. If the water is basic, chlorine can’t do its job as well, and you risk bacteria like salmonella and E. coli invading your pool. For all of these reasons, it is important to keep the pH in that “just right” zone of 7.2 to 7.8.

So, if pH ranges from acid to alkaline, why is there a separate measurement for alkalinity? It is reasonable to be confused about this, because an alkaline pH and total alkalinity sound like the same thing, but these two tests measure different chemicals. The pH of the pool is the concentration of Hydrogen ions, or the amount of carbon dioxide dissolved in the water. The total alkalinity measurement refers to the concentration of alkaline substances that are present in the water. These can attract and release Hydrogen ions, so measuring total alkalinity determines how well the water can resist a reduction in pH. Testing for both pH and total alkalinity gives you a more complete understanding of your pool water.

Sanitizing Your Pool

Sanitizing is crucial to keep your pool free from harmful bacteria, algae, and other microorganisms. There are a few different methods used for sanitizing a pool.

• Chlorine is the most commonly used sanitizing chemical. Available in liquid, granular, tablet, and stick form, and while it is effective in killing the bacteria, algae, and pathogens that make a pool unsafe, it is less effective when the pH is too high. Additionally, chlorine is volatile, and has an unpleasant odor.
• Bromine, a similar chemical to chlorine, is typically used in hot tubs and spas. It sanitizes effectively for a longer period of time than chlorine, without the chlorine odor, but it is more expensive, and sunlight can make it less effective.
• Ozone is produced by a generator attached to the circulation system. It is very effective, but has a short lifespan in water, so it is generally only used as a backup to a primary sanitizer.
• Ionization uses minerals like copper and silver to sanitize pool water. Copper gets rid of algae, and silver kills bacteria, and these minerals are not affected by water temperature, but they do not address organic components like soaps and oils.
• Salt chlorination is an alternative to chemical sanitizers. Installed into the pool’s plumbing, a saltwater chlorinator uses electricity to turn salt ions in the water to chlorine, producing a consistent supply. Sometimes, though, salt chlorination can make pH difficult to manage.

What Can Disrupt Your Pool Water Balance?

You should check your pool’s chemical balance by using a test kit once a week, and when it is off balance, it can be improved by adjusting the chemicals. Sodium bicarbonate increases alkalinity, and muriatic acid decreases it, and there are pH increasers or decreasers to stabilize the pH. If your chlorine is too low, you will need to add chlorinating products, but a high level requires diluting the pool water. Additionally, proper circulation and keeping your pool clean are both crucial to the quality of your pool water. Several factors can negatively impact your pool’s balance.

• Sunlight can degrade chlorine, but this can be mitigated using stabilizers like cyanuric acid.
• Rain can bring contaminants into the pool and dilute the chemicals, altering the balance of the pool chemistry.
• Warm weather can speed bacterial growth, increasing the demand for chlorine, while cool weather can reduce the effectiveness of your pool chemicals.
• Swimmers can introduce contaminants, including sweat, skin oils, cosmetics, and bacteria, which can affect the pool’s balance.

Trust Aaron Pools & Spas to Help Maintain Your Pool

If you need help keeping your pool clean and clear year-round, reach out to the professionals at Aaron Pools and Spas. Established in 1972, this family-owned-and-operated business has a dedicated, award-winning team with over 400 years of combined experience. We love to help improve the quality time that families spend together at home, and that’s why we’ve installed more than 2,000 swimming pools and hot tubs, from Cape Cod to Connecticut. We also offer pool covers, as well as pool cleaning products to make sure your pool looks beautiful, feels amazing, and is safe. For the best possible service from our highly experienced installation team, contact us today.