Dichlor in Pools: All You Need to Know

Dichlor is a stabilized, organic compound that appears in granular form. It offers 56-63% available chlorine and more than 99% active strength. In a 1% solution, it has a neutral effect on the pH, keeping it between 6.5 and 6.8.  Dichlor refers to Sodium dichlorostriazinetrione. It is a white granular, fast-dissolving chlorine compound with a near-neutral pH. It doesn’t cloud the water and can be used for regular and superchlorination. It has a built-in stabilizer (cyanuric acid). Dichlor is manufactured by adding sodium hydroxide to cyanuric acid in a controlled amount of water. This produces sodium cyanurate, which is then treated with chlorine gas to produce sodium dichloroisocyanurate, water, and sodium chloride.

Is Sodium Dichloroisocyanurate and Dicholor the Same?

Yes, Sodium Dichloroisocyanurate and Dichlor are the same. Sodium Dichloroisocyanurate is also known as sodium dichloro-s-triazinetrione or Dichlor. It is a chemical compound used as a sanitizer and disinfectant, and it is safe for use in various types of pools. It is available in two forms: anhydrous and dihydrate, and it provides free available chlorine. It also functions as an oxidizer and algaecide.

What is the Composition of Sodium Dichloroisocyanurate?

Sodium dichloroisocyanurate, in its purest form, provides 64.58% available chlorine. The cyanuric acid content is calculated similarly. The atomic weight of the cyanurate (CNO) in the formula is 126.0513. To find the cyanurate content, divide the cyanurate’s atomic weight by the total formula weight. This gives us 57.31% cyanurate by weight. However, due to impurities, the actual percentages are slightly adjusted and rounded.

How is Dicholor Produced?

Dichlor is produced by adding sodium hydroxide to cyanuric acid in a controlled amount of water. This produces sodium cyanurate, which is then treated with chlorine gas to produce sodium dichloroisocyanurate, water, and sodium chloride.  In more detail, the production process of Dichlor, or sodium dichloro-s-triazinetrione, begins with the addition of sodium hydroxide to cyanuric acid in a specific amount of water. This reaction results in the formation of sodium cyanurate. The sodium cyanurate is then treated with chlorine gas. This treatment leads to the production of sodium dichloroisocyanurate, along with water and sodium chloride. The chlorine gas used in this process is typically produced using electrolytic cells from a solution of salt, water, and electricity.

What Are the Chemical Properties of Dicholor?

Dichlor, also known as sodium dichloro-s-triazinetrione, is a white granular, fast-dissolving chlorine compound with a near-neutral pH. It provides 62 percent available chlorine and also comes in a dihydrate form, which provides 56 percent available chlorine. It has a built-in stabilizer (cyanuric acid) and doesn’t cloud the water. It can be used for regular and superchlorination. Dichlor reacts with water to form hypochlorous acid, cyanuric acid, sodium ion, and hydroxyl ion. It contains about 50% cyanuric acid in its 56% form and about 58% in its 62% form. For every 10 ppm of free chlorine added by dichlor to a pool, the cyanuric acid level increases by 9 ppm.

Is Dicholor Stable?

Yes, Dichlor is stable. It has a long shelf life of about 3 years and is a fast-dissolving chlorine compound with a near-neutral pH. It also contains a built-in stabilizer, cyanuric acid, which further contributes to its stability. However, it dissolves quickly, so it cannot be used in erosion feeders or most typical chlorinators.

What Are the Compatibility Considerations for Dicholor?

Dichlor can be used in any pool or spa, including vinyl-liner pools, fiberglass pools, painted pools, spas, and hot tubs. Its fast dissolving and near-neutral pH properties prevent damage to the vessel. However, it dissolves quickly, so it cannot be used in erosion feeders or most typical chlorinators. It can be pre-dissolved and added to water as a liquid, but this is impractical as you can only make about a 5% solution.

Where is Dicholor Used?

Dichlor is used in any pool or spa. It is particularly useful for owners of vinyl-liner pools, fiberglass pools, painted pools, spas, and hot tubs.  Dichlor, also known as sodium dichloro-s-triazinetrione, is a white granular, fast-dissolving chlorine compound with a near-neutral pH. It doesn’t cloud the water and can be used for regular and superchlorination. It is safe for use in all types of pools, including white plaster, colored plaster, vinyl liner, fiberglass, acrylic, and painted pools. However, it is not recommended as a regular chlorinating source. It can be added directly to the pool as it dissolves quickly and does not change the pH.

What Are the Benefits of Dicholor?

The benefits of Dichlor include its minimal effect on the pH and total alkalinity of water, even when used in large amounts. It can be beneficial even if other chlorine compounds are used. For instance, when starting a new pool, Sodium Dichlor can be used as a source of cyanuric acid, often cheaper than buying pure cyanuric acid. It is also useful for owners of vinyl-liner pools, fiberglass pools, painted pools, spas, and hot tubs due to its fast dissolving and near-neutral pH properties. Furthermore, Dichlor provides a significant amount of available chlorine and has a built-in stabilizer (cyanuric acid). It doesn’t cloud the water and can be used for regular and superchlorination.

How to Apply Sodium Dichloroisocyanurate?

This compound can be added directly to the pool. It dissolves quickly and does not change the pH. However, it should not be allowed to sit on the bottom of colored plaster, vinyl liner, fiberglass, acrylic, or painted pools.

How to increase Chlorine in the pool with Dicholor?

To increase chlorine in the pool with Dichlor, you can add the compound directly to the pool. It dissolves quickly and does not change the pH. However, it should not be allowed to sit on the bottom of colored plaster, vinyl liner, fiberglass, acrylic, or painted pools. The amount of Dichlor needed can be calculated by determining the desired increase in parts per million (ppm) of chlorine in the pool, dividing the pool’s volume in gallons by 10,000, and referring to the chlorine dosage table to find the amount of chlorine needed to increase the chlorine level by 1 ppm. Multiply these values to get the total amount of Dichlor needed.

What Happens When Dicholor is Added to Water?

When dichlor is added to water, it hydrolyzes to form sodium cyanurate and hypochlorous acid. The chlorine atoms in sodium dichlor hydrolyze to form hypochlorous acid, leaving cyanuric acid to protect the chlorine from sunlight.

How Does Sodium Dichlor React with Water?

When sodium dichlor is added to water, it hydrolyzes to form sodium cyanurate and hypochlorous acid. The chemical reaction is represented as: NaCl + C3N3O3 + 2H2O → NaH + C3N3O3 + 2HOCl. In this reaction, the chlorine atoms in sodium dichlor hydrolyze to form hypochlorous acid, leaving cyanuric acid to protect the chlorine from sunlight.

What is the Chemical Reaction of Dichlor Dihydrate and Water?

Dichlor dihydrate reacts with water to form hypochlorous acid, cyanuric acid, sodium ion, and hydroxyl ion. The chemical equation is: NaCl2CNO•2H2O + H2O → 2HOCl + H3CNO + Na+ + OH–

How Can You Test Dicholor?

You can test Dichlor using DPD, FACTS, TMP Test Kit or Test Strips. It should be tested weekly or more often if heavily used. The recommended level is 7.5% of CYA or 5.0% of CYA with borate 50 ppm.  Dichlor, also known as Sodium Dichloroisocyanurate, can be tested using various methods such as DPD (diethyl phenylene diamene), FACTS, and TMP. These methods involve the use of test kits or strips that can determine the actual free chlorine in a sample. The testing should be done on a weekly basis or more frequently if the Dichlor is heavily used. The recommended level for testing is 7.5% of CYA (Cyanuric Acid) or 5.0% of CYA with borate 50 ppm.