top of page
  • Writer's pictureHopkins Custom Pools

Pool Chemistry 101

When it comes to swimming pools, the right chemicals are needed to keep the water sparkling clean and crystal clear. However, these chemicals cannot simply be dumped into an owner’s custom pool and expected to work. They must be added in the right amounts and at the right time. With that in mind, here’s a brief primer on the types of chemicals needed for a sanitary and beautiful pool: 

Water Clarifiers: 

These chemical are added to the water if it is turbid. This does not mean that the water is too unhealthy to swim in but that it has microscopic particles floating in it that make it look dull. These particles also have an electrical charge that causes them to repel each other. The water clarifier contains particles of the opposite charge that attract and capture the particles and make them easier to filter out. A stronger type of water clarifier is called a flocculent. This causes the particles too clump together, and fall to the bottom of the pool. That way, the customer or the pool company can remove them with the pool vacuum. 

Chemicals Used to Balance the Water

Water that is considered balanced has certain chemical criteria. They include: 

  • A pH that is between 7.2 and 7.8. This is slightly alkaline.

  • A total alkalinity that’s between 80 and 120 parts per million

  • A calcium level that’s between 100 and 400 ppm

  • Total dissolved solids, or TDS of between 250 and 1500 ppm

  • No minerals that can stain

Water that does not have these values can be hard which leads to limescale and cloudiness. If the levels are very much out of balance, the water is said to be aggressive. This type of water can corrode the pool equipment and even destroy the pool shell. 

Chemicals used to bring the levels into balance are: 

  • Chlorine, which helps to sanitize the pool. Chlorine also helps adjust the custom pool’s pH level. Chlorine tablets lower the pH, while liquid chlorine raises it.

  • Soda ash, which raises the pH if it’s too low.

  • Muriatic acid or sodium bisulfate, which lower the pH if it’s too high.

  • Sequestering agents are chemicals added to water whose calcium levels are too high. They dissolve the calcium so that it is not as likely to create limescale or make the water cloudy. 

  • Bromine, which is a relative of chlorine and is most often used in hot tubs.

  • Biguanide or PHMB is another pool sanitizer. Pool owners who prefer it cite that it does not have a chlorine smell and does not irritate skin like chlorine does.

  • Ozone is used to kill microorganisms, but it is not long-lived and needs to be used with chlorine or bromine. The benefit of ozone is that reduces the levels of chlorine or bromine that need to be used to keep the pool clean.

For more information about Pool Chemistry 101, call our professionals at Hopkins Custom Pools the premier pool builder in Dallas, Texas. Visit our website at


bottom of page