Dichlor and Trichlor

Posted by www.poolplantcourses.org on Tuesday, January 17, 2012 Under: Pool Water Chemistry
For the purposes of pool plant operation, chlorinated isocyanurates (also referred to as stabilised chlorine) can be thought of as a combination of cyanuric acid and chlorine. Why would a pool plant operator want cyanuric acid in addition to just chlorine? The answer is because in outdoor pools that are exposed to sunlight, the chlorine will get diminished by the UV in the sunlight. It needs an additional chemical to be added to prevent this from happening. This chemical is cyanuric acid. It is possible to simply add some cyanuric acid (which comes as a white crystalline power) to the circulation system in conjunction with sodium/calcium hypochlorite. Many outdoor pool operators prefer to add a chemical that contain both the chlorine and the cyanuric acid. There are two chemicals on the market:

1.  Dichloroisocyanuric acid 
55% available chlorine. Comes as a white powder. pH is around 6.5.

2.  Trichloroisocyanuric acid 
90% available chlorine. Comes as either white powder, granules or tablet. pH is around 3.0.

Dichlor and trichlor should never be mixed. When choosing one, the main factors to consider would be the method of dosing, the pH levels and how these are going to affect the rest of the pool plant system, and the amount of available chlorine in each product.

In : Pool Water Chemistry 

Tags: dichlor trichlor "stabilised chlorine" "chlorinated isocyanurates"