Pool chlorine – one of my favorite topics! Hello again, I’m Dr. Pool, resident chemist at In The Swim.
Why would a chemist work for a pool supply retailer? To create & test our own chemical formulations, in a state of the art compounding facility.
Is all pool chlorine the same? The short answer is NO ~ Trichlor tablets may look the same, but they differ in “materials and workmanship”.
Chemical labeling and MSDS sheets provide a look into the ingredients used in chlorine tablets and pool shock, but manufacturers are allowed “proprietary” license, to not list trade secret ingredients.
Trichlor tablets can contain additives to control algae or improve water clarity. In such cases, a lower percentage of available chlorine will tip you off to the use of fillers or additives.
Cheaper binders can gum up chlorinators and cloud pool water. Raw materials can contain impurities or be cut with low grade fillers in cheap chlorine.
How chlorine is made does make a difference in the level of impurities, and in how the chlorine is delivered. Cheaper tableting equipment can produce a crumbly tablet that dissolves too rapidly.
A chlorine product’s solubility, hardness and bulk density affects the release rate and is dependent upon the heat and pressure used during tablet formation, as well as the quality and purity of ingredients.
It takes a lot of pressure and heat, and precise cooling to create a well-made chlorine tablet, and do it without harm to the environment. Less sophisticated tableting facilities produce an inferior product and discharge excessive byproducts into air and water.
Country of Origin
In recent years, chemical manufacturers in the U.S. have petitioned the International Trade Commission for protection and sanctions against imported isocyanurate products being dumped on the U.S. market.
Late last year, the Dept of Commerce ruled that imported Chinese chlorine was found to be heavily subsidized by the Chinese government, and was unfair to domestic manufacturers.
The effects have already caused one major US chlorine manufacturer to stop producing pool chlorine – Chemtura. Tariffs will increase for Chinese chlorine, which likely will force cost cutting measures to maintain profit on their investments.
Differences in Chlorine
In a nutshell, there are significant differences in the quality of chlorine tablets and pool shock. This results in tablets that dissolve too rapidly and leave a gummy residue, and granular products that separate too slowly, and leave behind a cloudy residue.
There are many ways to make a cheap chlorine product, so stick with a major brand; and avoid private label brands and sales on “Generic” pool chlorine from big box retailers, home stores or discount clubs, which are domestically packaged with imported chlorine.
No matter what type of chlorine you use – Trichlor, Dichlor or Cal Hypo – look for a respected brand of domestic pool chlorine, and steer clear of chlorine products of dubious origin or of poor materials and workmanship.