Trichlor in Pools: All You Need to Know

Trichlor is a stabilized, organic compound that comes in granular form or tabs. It has 90% available chlorine and more than 99% active strength. In a 1% solution, it lowers the pH to a range of 2.8 to 3.5.  Trichlor, also known as trichloro-s-triazinetrione or trichloroisocyanuric acid, is a chlorine compound that provides 90% available chlorine, the highest of any chlorine compound. It’s a white, slow-dissolving acidic pH chlorine compound that won’t cloud the water and can be used for regular chlorination but not superchlorination. Its pH ranges between 2.8 and 3.0 and it has a built-in stabilizer.

What is Trichloroisocyanurate?

Trichloroisocyanurate, also known as trichlorostriazinetrione, is a chemical compound with the CAS Number 89901 and UN ID Number UN2468. It falls under the NFPA Storage Class I. The maximum storage for a nonsprinklered area is 18,000 lbs. Its chemical formula is Cl3C3N3O3.

What are the Chemical Properties of Tricholor?

Trichlor, also known as trichloro-s-triazinetrione or trichloroisocyanuric acid, provides 90% available chlorine, the highest of any chlorine compound. It’s a white, slow-dissolving acidic pH chlorine compound that won’t cloud the water. Its pH ranges between 2.8 and 3.0 and it has a built-in stabilizer (conditioner or cyanuric acid). Trichlor reacts with water to form hypochlorous acid and cyanuric acid. It contains a stabilizer and is available in tablet form. It increases total dissolved solids (TDS) by 16 ppm per 10,000 gallons. Its pH ranges from 2.9 to 3.5. It has a shelf life of 3 years. The chemical formula of Trichloroisocyanurate is Cl3C3N3O3.

How much Chlorine is in Tricholor?

Trichlor contains about 90% available chlorine. This means that a container of trichlor can release 90% of the chlorine that 100 pounds of chlorine gas would when dissolved in water. However, to quickly determine the actual chlorine content in a product, divide the stated available chlorine content percent by 2. Therefore, 90% available chlorine trichlor is about 45% chlorine.

How is Trichlor produced?

Trichlor is produced by adding sodium hydroxide to cyanuric acid to create sodium cyanurate, then adding chlorine gas under controlled conditions to get trichloroisocyanuric acid, water, and sodium chloride. The manufacturing equation is as follows: Cyanuric acid + sodium hydroxide yields sodium cyanurate. Sodium cyanurate + chlorine gas yields trichloro-s-triazinetrione + sodium chloride.

What is the Chemical Reaction of Trichlor and Water?

Trichlor reacts with water to form hypochlorous acid and cyanuric acid. The chemical equation is: Cl3CNO + 3H2O → 3HOCl + H3CNO3

What Happens When Tricholor is Added to Water?

When trichlor is added to water, it reacts to form cyanuric acid and three hypochlorous acid molecules. This reaction involves nine steps, with each of the three chlorine molecules in trichlor ultimately forming three hypochlorous acid molecules. The chemical equation for this reaction is: Cl3CNO + 3H2O → 3HOCl + H3CNO3. Trichlor contains cyanuric acid, also known as a stabilizer or conditioner, which protects chlorine in water from sunlight. However, high levels of cyanuric acid can slow down chlorine kill times and require higher levels of free chlorine for disinfection and oxidation. Trichlor is highly acidic with a pH of 2.8-3.0, and if used improperly, it can damage equipment, plaster, vinyl, fiberglass, and acrylic.

Where is Tricholor used?

Trichlor is used in white and colored plaster pools with an in-line or off-line chlorinator.  Trichlor, or trichloro-s-triazinetrione or trichloroisocyanuric acid, is a chlorine compound used for regular chlorination of pools. It is typically sold as a slow-release tablet and is suitable for use in floating chlorinators, erosion-type feeders, and automatic in-line or off-line chlorinators. However, it is not recommended for use in vinyl liner, fiberglass, acrylic, or painted pools due to the quick build-up of CYA, requiring a higher free chlorine level. It is also used as a primary sanitizer and disinfectant, killing all living microorganisms and disease-causing organisms in the pool water.

How is Tricholor Used?

Trichlor is used as a slow-release tablet in floating chlorinators, erosion-type feeders, and automatic in-line or off-line chlorinators. It’s suitable for regular chlorination but not for superchlorination due to its slow dissolution rate. It is also used as a primary sanitizer and disinfectant, killing all living microorganisms and disease-causing organisms. Additionally, it acts as an oxidizer and algaecide.

How to increase Chlorine in the pool with Tricholor?

To increase chlorine in the pool with Trichlor, you can add it directly to the pool water. Trichlor reacts with water to form cyanuric acid and three hypochlorous acid molecules, which increase the chlorine level in the pool. However, it’s crucial to keep the floater, whether it’s a floating duck or dispenser, away from any metal or skimmer intake. Trichlor tablets should never be placed in the skimmer, as their acidic properties can dissolve metal.  For a more specific dosage, you can use a simple formula to calculate the amount of chlorine needed for your pool size and desired chlorine level. Determine the desired increase in parts per million (ppm) of chlorine in the pool, divide the pool’s volume in gallons by 10,000, refer to the chlorine dosage table to find the amount of chlorine needed to increase the chlorine level by 1 ppm, and multiply the values from these steps to get the total amount of chlorine needed.  Remember, Trichlor is about 50% cyanuric acid. Therefore, adding 10 ppm of trichlor to a pool increases the cyanuric acid level by 6 ppm. If you use a lot of trichlor, you could quickly reach 50 ppm of cyanuric acid. High levels of cyanuric acid slow down chlorine kill times and require higher levels of free chlorine for disinfection and oxidation.

Are there types of trichlor for skimmer use?

Certain types of trichlor tablets and sticks are specifically designed for skimmer use. They contain slow-dissolving chemicals and buffers to prevent damage. However, these are also dangerous if mishandled. Regular trichlor tablets or sticks are not recommended for skimmer use.

What are the compatibility considerations for Trichloroisocyanurate?

Trichloroisocyanurate can be used in white and colored plaster pools with an in-line or off-line chlorinator. It is not recommended for use in vinyl liner, fiberglass, acrylic, or painted pools due to the quick build-up of CYA, requiring a higher free chlorine level.

Does mixing cal hypo and trichlor cause an explosion?

Yes, mixing cal hypo (calcium hypochlorite) and trichlor (trichloroisocyanurate) with a small amount of water can cause an explosion and fire. This reaction produces hydrogen and chlorine gas and a large amount of heat, enough to ignite the hydrogen gas. This happens to pool owners a few times each summer when they unknowingly mix different types of chlorine tabs in their floating chlorinators.

What are the Benefits of Tricholor?

The benefits of Trichlor include its high available chlorine content, slow-dissolving nature, and built-in stabilizer. Trichlor provides 90% available chlorine, the highest of any chlorine compound. Its slow-dissolving nature makes it ideal for use in floating chlorinators, erosion-type feeders, and automatic in-line or off-line chlorinators. It also contains a built-in stabilizer (cyanuric acid), which protects chlorine in water from sunlight.  Trichlor is primarily used as a sanitizer and disinfectant, effectively killing all living microorganisms and disease-causing organisms in pool water. It also acts as an oxidizer and algaecide. Its slow dissolving nature ensures that chlorine is released into the water daily, even if the pool isn’t serviced regularly. Furthermore, Trichlor contains cyanuric acid, also known as a stabilizer or conditioner, which protects chlorine in water from sunlight, extending its effectiveness. However, it’s important to note that Trichlor is highly acidic and can cause damage if used improperly.

Is Tricholor stable?

Yes, Trichlor is stable. Trichlor, or trichloroisocyanurate, is a compound that contains a stabilizer and is typically sold in a slow-release tablet form. It has a shelf life of 3 years, indicating its stability over time. Furthermore, it is produced by adding sodium hydroxide to cyanuric acid to create sodium cyanurate, then adding chlorine gas under controlled conditions to get trichloroisocyanuric acid, water, and sodium chloride. This manufacturing process also suggests its stability.

What are the risks of using trichlor tablets?

Even pools with 24/7 pump operation can have issues with acid from the tablets dissolving metal. Moreover, placing multiple tablets in the skimmer increases the acid level. Another risk is that people, especially children, can easily access these dangerous tablets, which can cause permanent eye damage in just 15 seconds.

How Can You Test Tricholor?

Testing methods for Trichloroisocyanurate include DPD, FACTS, and TMP. Test kits or strips can be used. Testing should be done weekly or more often if heavily used. The recommended level is 7.5% of CYA.  Trichloroisocyanurate, also known as Trichlor, can be tested using various methods such as DPD (N,N Diethyl-1,4 Phenylenediamine Sulfate), FACTS (Free Available Chlorine Test Solution), and TMP (Taylor Monopersulfate). These methods involve the use of test kits or strips that react with the Trichlor in the water to indicate its concentration. The testing should be conducted weekly, or more frequently if the pool or spa is heavily used. The recommended level of Trichlor in the water is 7.5% of Cyanuric Acid (CYA), a stabilizer that protects chlorine from sunlight degradation.

How to store Tricholor?

Trichloroisocyanurate should be stored in a cool, dry, well-ventilated area. It should be kept in its original container with the cap or lid securely replaced to prevent spills and maintain chemical efficacy. The maximum storage for a nonsprinklered area is 18,000 lbs.

How is Trichlor Sold?

Trichlor is typically sold as a slow-release tablet, either 1-inch (0.5 oz. or 28 grams) or 3-inch (7 oz. or 200 grams). It’s also available as an 8 oz. stick or a large 28 oz. tablet.  These tablets and sticks are designed to be placed in a skimmer. The slow-release nature of Trichlor makes it ideal for use in floating chlorinators, erosion-type feeders, and automatic in-line or off-line chlorinators. It’s suitable for regular chlorination but not for superchlorination due to its slow dissolution rate.