Difference Between Trichlor and Dichlor

The key difference between trichlor and dichlor is that the Trichlor (or trichloro-s-triazinetrione) is a dry solid compound having the highest possible chlorine content (around 90%) whereas, the Dichlor (or dichloro-s-triazinetrione) is available as its dihydrate form or the anhydrous form.

The chlorine content of the dihydrate form of the dichlor is around 56% while the chlorine content in anhydrous form is about 62%. The main use of both these compounds is mainly in cleaning swimming pool water, spa water and hot tubs.

1. Overview and Key Difference
2. What is Trichlor
3. What is Dichlor
4. Side by Side Comparison – Trichlor vs Dichlor in Tabular Form
5. Summary

What is Trichlor?

Trichlor is the short name for trichloro-s-triazinetrione. Trichloroisocyanuric acid is another name. It is a solid dry compound with the highest possible chlorine content. It contains about 90% chlorine. People use these compounds to clean water in swimming pools, spa, and hot tubs.

Figure 1: Chemical Structure of Trichlor

Trichlor adds cyanuric acid to water. This acid is useful in stabilizing the free chlorine in the water. Since it is a solid containing concentrated chlorine, it provides the residual level of chlorine required to kill pathogenic organisms in water. Moreover, it destroys the contaminants (such as those found in sweat, urine, etc.) found in water. Therefore, it acts as a sanitizer.

Trichlor is commercially available in granular and tablet form. Furthermore, this compound is completely soluble in water, and it does not contain any calcium. It is suitable for hard water cleaning as well. The pH and the total alkalinity of water considerably reduce when we add trichlor to the water. When it dissolves in water, it produces hypochlorous acid and hypochlorite ion (also known as free available chlorine). The hypochlorous acid acts as a biocide.

What is Dichlor?

Dichlor is the short name for dichloro-s-triazinetrione. This compound is available in two forms as dihyrate form or anhydrous form. The dihydrate form contains around 56% chlorine while the anhydrous form contains around 62% chlorine. Therefore, it is useful in treating water in swimming pools, spa, and hot tubs.

Application of this compound to water increases of residual chlorine level required to kill pathogenic organisms in water. It also acts as an algaecide as well as a sanitizer.

Unlike the application of trichlor, the application of dichlor slightly reduces the pH and total alkalinity. This compound is completely water soluble. It also produces hypochlorous acid and hypochlorite ion when dissolved in water. Dichlor is typically sold in granular form. However, it depends on the its form: dihydrate form or anhydrous form.

What is the Difference Between Trichlor and Dichlor?

Trichlor vs Dichlor
Trichlor is the short name of trichloro-s-triazinetrione.	Dichlor is the short name of dichloro-s-triazinetrione.
Physical State
Available in the dry solid form.	Available in the granular form
Types
No different types	Two different types as dihydrate and anhydrous form
Chlorine Content
Has about 90% chlorine	Has either 56% in dihydrate form or 62% in anhydrous form.
Function
Can kill pathogenic organisms in the water	Can kill pathogenic organisms as well as algae in the water.

Summary – Trichlor vs Dichlor

Trichlor and dichlor are two forms of chlorine containing-compounds used in cleaning water of swimming pools, spa and hot tubs. The key difference between trichlor and dichlor is that trichlor is a dry solid compound having the highest possible chlorine content (around 90%) whereas dichlor is available as the dihydrate form or the anhydrous form.

Reference:

1. “TriChlor and DiChlor — What Do They Have in Common?” Another Perfect Pool News, 12 Dec. 2011, Available here.
2. “Sodium Dichloro-S-Triazinetrione (Dichlor).” The Association of Pool and Spa Professionals. Available here.