Pool Chemicals 101: Everything You Need to Know

Pool Chemicals 101: Everything You Need to Know

Maintaining a pool can feel intimidating at the start. With so many different chemicals, levels, balances, and more to take into consideration, it can feel overwhelming to dive in!

We’re here to help break down the importance of each chemical, its function, and how it contributes to a comprehensive pool management system.

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What are Pool Sanitizers and What Do They Do?

Pool sanitizers attack bacteria, viruses, algae, and other natural contaminants in your pool to destroy them; the two most popular pool sanitizers are chlorine and bromine.

Sanitizers are the most important pool chemical, but they work best when all of the other levels in your pool — alkaline, pH, and calcium hardness — are balanced as well. It takes more than just sanitizers to keep your pool in great shape!

pool chemicals result in great pools

Is There a Difference Between Chlorine and Bromine?

There are a few differences between the two chemicals. Chlorine neutralizes bacteria and viruses by attaching to them and changing their chemical profile; once this happens, the chlorine is no longer effective, but the contaminants are gone.

On the other hand, bromine is similar to chlorine, but works better in pools, spas, and hot tubs that run at warmer temperatures. In particular, bromine is a great option for people whose skin is sensitive to chlorine – it is actually chlorine-based, however, in case you have anyone who is allergic to chlorine. While bromine can be more expensive than chlorine, it actually ionizes the bacteria and viruses and then continues to work, unlike chlorine.

Chlorine 101:

  • The ideal target balance for chlorine is 3ppm (parts per million). If you are under 3ppm, your pool is probably starting to become a petri dish. Anything more than 3ppm, and you probably need to dilute the chemicals in your water.
  • Most brands of chlorine are pretty similar. If you’re looking for a reason to buy one over another, check the “active ingredients” list which is what actually works to destroy the bacteria.
  • Weekly pool shocks are required with chlorine to clean the pool.

Bromine 101:

  • The ideal target balance for bromine is between 3ppm (parts per million) and 5ppm.
  • Weekly pool shocks are required with bromine to clear the pool.
  • Bromine does not add cyanuric acid or chlorine to the water.
  • Bromine is less stable than chlorine when exposed to the sun, so you need to make sure you are constantly checking your pool chemical levels.

What Other Chemicals Do I Need for my Pool?

If you only used pH products, alkalinity products, calcium products, sanitizers, you could keep a clean and healthy pool all year long. However, there are a few more products you should be familiar with in case you need or decide to use them.

Cyanuric Acid or Stabilizer

If you start with freshwater, you’ll want to add some cyanuric acid, also known as water stabilizer, as a base so that the chlorine doesn’t get burned off by the sun’s UV rays so quickly. Essentially, this chemical protects your chlorine from the sun.


As the name suggests, algaecide is an algae preventative. There are certain algaecides on the market that claim to kill algae, but the best killer is chlorine. Use algaecide as a backup; for example, if your chlorine levels dip down, and you don’t catch it in time, the algaecide will keep the algae at bay until you can get the chlorine levels back up.

Clarifier and Floc

A water clarifier helps by bringing all those tiny particles that are making your water cloudy and combining them into bigger particles that your filter will have a better chance of catching and removing.

Another option is known as floc, or flocculant, which grabs those tiny particles, brings them together and sinks them to the bottom. With pool floc, you will have to manually get those particles out of your water by vacuuming to waste.

What is Pool Chemical Testing?

When it comes to pool maintenance and keeping a stunning pool, measuring chemical levels is the first and most important step. After all, if you don’t know the status of your pool’s chemical levels, you won’t know how to correct and get back in balance!

There are a few methods to accomplish regular, consistent pool chemical testing. Typically, you can use test strips at home, or take a water sample to your local pool store to determine what you need to adjust.

However, there are also digital pool test kits available that automatically check your pool water 24/7 and send you alerts if anything needs to be adjusted so all you have to do is fix what’s broken.

how to balance pool water

How to Balance Pool Water

Balancing pool water entails monitoring the pH and alkalinity levels of your pool to ensure the perfect balance is struck. For this reason, it’s important to keep your eye on the pH and alkalinity levels of your pool – at least once a week – by using a home test kit or test strips.

To keep your pool balanced, you need to keep these chemicals on hand:

  • pH Increaser
  • pH Reducer (hydrochloric acid)
  • Alkalinity Increaser

Take note that you don’t need an alkalinity decreaser. Here’s why:

  • If your pH and alkalinity are low, alkalinity increaser will raise both. You may need to add a little pH increaser if the pH doesn’t reach 7.4.
  • If your pH and alkalinity are both high, pH decreaser will lower both.
  • If just your alkalinity is high, your pH will also be high and you can use pH decreaser.

If your pool is properly balanced at all times, it will make your pool’s sanitizer work more effectively – especially chlorine.

What is a Pool Shock?

Pool shocks clean your pool when its sanitizer – chlorine or bromine – is overworked and needs to have the remnants removed from the pool, which is why interval pool shocks are so critical.

You may want to shock or superchlorinate your pool after specific events as well like a heavy rainstorm, a big pool party, or a few small children who may or may not have accidents!

Shocking your pool on a weekly basis with non-chlorine shock eliminates bacteria without shifting your chlorine levels and goes a long way towards keeping it balanced.

Pool Shock 101:

  • Shock your pool every week. Seriously. A smart water monitoring system will remind you to shock your pool so it’s always ready and waiting for you to have fun.
  • Pool shock chemicals aren’t stabilized, so it’s best to shock your pool in the late afternoon or evening. Make sure to run the pump for several hours to make sure the chemicals are spread evenly and working.
  • If you use a chlorine-based pool shock, make sure you know how long the manufacturer recommends waiting before allowing swimmers into the pool.

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