The inverse of heat is cold, and as water temperatures decrease the activity of these lingering waterborne growths and pathogens also decrease. When growth and activity decreases, the overall need for oxidizers lessens as well. Just like when the pool is open, when it is closed there is equal importance in reducing and eliminating these precursors to water issues or at least keeping them under control.
Lessen the shock upon pool opening
When the season winds down, shocking the pool water is a must to reduce the number of contaminants. After the water is shocked, contaminant loads are reduced which frees up the disinfectant (sanitizer) to help control the other materials lingering in the water—either currently or other contaminants that may get into the pool during the off-season.
There are two different camps in what works best. On one end, there are those who like to use chlorinated products, while on the other, there are those using non-chlorine oxidizing shocks.
Using chlorinating products to close a pool has its advantages. If chlorine levels are non-existent then administering a chlorinating shock will simultaneously scourer the pool of algae, bacteria, and other contaminants, while leaving a lingering amount of chlorine for the closing period. When unstabilized chlorines are used, the impact to the water’s pH is minimized.
Non-chlorine oxidizing shocks, relative to chlorine, is still an up and comer in the recreational water maintenance industry. Since most are comfortable with chlorine’s abilities, most do not look at non-chlorine as an effective tool—especially when it comes to closing a pool. However, just because the product does not have chlorine present does not make it any less of an oxidizer.
Non-chlorine oxidizers can scour more contaminants in the water than its chlorine predecessor. And since it does not contain any chlorine, it will not interact with chlorine and possibly form any disinfection byproducts. Most importantly, its lack of chlorine is better for the long-term appearance of the pool’s surface. Regardless of its effectiveness as an oxidizer, a chlorine presence during the off-season is still a must.
Kevin Vlietstra is the technical director and regulatory specialist with Haviland Pool and Spa Products. He has been working in the recreational water industry for more than 20 years. He can be reached via email at kevinv@havilandusa.com.
