What Chemicals Do You Need for a Pool

Pool chemistry is one of the more confusing aspects pool owners have to deal with, but it is one you have to learn in detail about to make the pool a safe swimming environment. However, with an abundance of pool chemicals out there, most of them boasting rather intimidating scientific names, and tending to different tasks in terms of pool cleaning, it gets indeed difficult to understand proper pool water chemistry. In the following, we will explore this subject more so that you not only know what chemicals you must stock up on, but what their purpose is as well.

Why Pool Chemicals Are a Necessity

Although you might not be a fan of the idea, there is no other viable method to keep the pool 100% clean and safe for swimming except for adding the occasionally needed chemicals and maintain proper water chemistry. Sure, vacuuming the pool’s surfaces and filtering out the debris lurking in the water does make it a safe habitat to swim in, but without pool chemicals, there will still be pH unbalances, algae, and bacteria to worry about.


There are two main reasons why all pool owners must get used to adding the right chemicals at the right time – for safety and for the sake of aesthetics. From the safety point of view, it is easy to understand why you must do this chore as, without proper treatment, the pool becomes contaminated with dangerous microorganisms, bacteria, and algae. When it comes down to aesthetics, not only will algae contamination make the body of water repulsive, but the pool water will never get that sparkling blue appearance it gets in nature.

List of Sanitizers

Undoubtedly the most important category of pool chemicals, sanitizers fulfill the purpose of keeping bacteria and algae growth under control, reducing the risk of microorganisms inhabiting the water, and maintaining water clarity.


  • Most commonly used sanitizer – used in all public and community pools;
  • Found in three forms – tablet, liquid, and granular;
  • When added in outdoor pools, it must be used in its stabilized tablet form to not break down from the UV light.

Tablet chlorine is the preferred option for basic, regular maintenance, while the liquid and granular forms are recommended for use in shock treatments.


  • Can be found in granular and tablet form;
  • As it is sensitive to UV light, in case it is used for an outdoor or exposed pool, constant replenishment is necessary;
  • Highly effective at killing algae, even better than chlorine;
  • A bit more expensive than chlorine.

Polyhexamethylene Biguanide

  • Should not be used in combination with bromine and chlorine as it is incompatible with them;
  • Great option for ridding the pool of algae and bacteria;
  • Swimmer-friendly sanitizer;
  • Longer lifespan in the water makes it easier to maintain;
  • You are required to add hydrogen peroxide-based oxidizer once per week to upkeep the chemical.

List of Algaecides

The battle against algae in the pool seems never-ending. However, there is one solution to put an end to this tedious war, more precisely by using pro-grade algaecides that will tend to kill all algae and prevent the appearance of this issue ever again.


  • Other benefits include improved clarity of the water, reduced need to use sanitizers, and reduced skin and eye irritation;
  • Most effective in ranges of 30 to 50ppm;
  • As it renders algae incapable of processing carbon dioxide, it inhibits its growth altogether.

Bromine Salts

  • Effective at killing black and mustard algae;
  • If you use it during a shock treatment, it creates hypobromous acid which is highly effective at killing algae;
  • Should only be used in chlorine and bromine compatible systems.

Quaternary Ammonia

  • One of the most common chemicals used to fight algae;
  • Found in liquid form, and ranges in concentrations from 5 to 50 percent;
  • When used in an overdose, it causes foam to appear at the top of the pool water.


  • Unlike quaternary ammonia, it does not cause foaming;
  • Most commonly found in concentrations ranging from 50 to 60 percent;
  • Better at killing and preventing algae growth than regular quats;
  • One of the more expensive chemicals.

List of Water Balancers

As the name makes it more than obvious, water balancers serve the purpose of ensuring proper balance in the chemistry of your pool’s water. The aspects we refer to when talking about balance are the pH level, alkalinity level, and water hardness.

Alkalinity Increasing Chemicals

  • They raise water alkalinity levels without actually affecting pH levels;
  • Commonly used alkalinity increasing chemicals include baking soda and sodium bicarbonate;
  • Available in convenient to use powder form.

Alkalinity Decreasing Chemicals

  • Commonly used alkalinity decreasing chemicals include sodium bisulfate and muriatic acid;
  • As while they lower the total alkalinity, pH levels are lowered as well, adjustment to the pH level is needed after using these chemicals;
  • Available in liquid form – muriatic acid – and in powder form – sodium bisulfate;
  • Be cautious when using these strong acids – make sure to follow the instructions given on the label.

Calcium Chloride

  • Helps increase the total hardness of the water;
  • Can be acquired in of two forms – liquid or granular;
  • It is better to add small doses of calcium chloride with 2-4 hours break between the sessions.

pH Increasing Chemicals

  • Most commonly used chemicals include soda ash and sodium carbonate;
  • Help increase the pH level of the water you swim in;
  • Available in liquid and powder form.

pH Decreasing Chemicals

  • Most commonly used chemical is sodium bisulfate;
  • Tends to lower pool pH level rapidly;
  • Only slight lowers alkalinity during the process;
  • Available in liquid and powder form.

List of Shocks and Oxidizers

Shocks and oxidizers serve the purpose of aiding sanitizers to control algae and bacteria growth, destroying sanitizer bi-products and organic compounds so that sanitizers become more effective at their job.

Lithium Hypochlorite

  • Granular chlorine which dissolves extremely fast;
  • One of the best oxidizers, but one of the most expensive solutions as well;
  • Its components make it raise chlorine level in the water in smaller levels than other options do;
  • Boasts a high pH of approximately 10.7.

Calcium Hypochlorite

  • Can be acquired either in tablet or granular form;
  • High pH of approximately 11.8;
  • Slightly increases calcium hardness levels;
  • Generally found in strengths of up to 78 percent.

Sodium Hypochlorite

  • Ranges in strength from 6 to 12 percent;
  • Dissipates rapidly in UV light;
  • Powerful algae treatment due to its fast acting;
  • High pH of approximately 13.0.

Non-Chlorine Oxidizer

  • Comes in two popular forms – monopersulfate and potassium peroxymonosulfate;
  • Primary option for shock treatment in bromine pools;
  • Reacts very quick, allowing you to use the pool after only 15-20 minutes.

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