Low Pool Chlorine & Stabilizer

by JIM
(WEST DUNDEE IL)

About low swimming pool chlorine level, stabilizer, and cyanuric acid...

My pool is 27000 gallons. The pH level is good and the swimming pool is very clean, but I cannot keep any chlorine in pool.

The pool store told us to use stabilizer in pool, so we put it in sock and tied it to ladder as we were told to do. They said it would take the stabilizer 2 weeks to work. Is this true?

Every year I have same problem. Do I need to keep solar cover on? I do have swimming pool heater and I could use some help.

Thank You

Jim G

Thanks for your question Jim

You seem to have an issue that many swimming pool owners face; a loss of pool chlorine. The main reason that pools will lose the chlorine level quickly, even after a good pool shock, is because of low cyanuric acid (CYA). This kind of acid is used as a stabilizer for your pool chlorine.

Chlorine Tablets.. Swimming Pool Chemistry..Care..Maintenance

Swimming Pool Chlorine..Chemistry..Above Ground Maintenance..Care..

There are basically two ways to add cyanuric acid to the pool; with chlorine tablets (Trichlor pucks or tabs) and granules (Dichlor).

Dichlor, or sodium dichloroisocyanurate, is a granular, stabilized, and fast dissolving form of pool chlorine and is often used as a pool shock.

While Dichlor does add pool chlorine it will also increase your CYA level while lowering your pool water pH level. Take care in using Dichlor as your CYA can get out of hand very quickly.

Trichlor, or trichloroisocyanuric acid, are sold as 1" and 3" tablets or pucks that you can either put into a swimming pool floater or a chemical feeder.

When the water passes over the tablets they dissolve to increase the swimming pool chlorine and cyanuric acid level in the pool. They will also lower the swimming pool pH levels because they tend to be on the acidic side.

The best way to test your CYA is by using the right pool water testing kit. I've always used a Taylor Reagent FAS-DPD K 2005 or 2006 water testing kit.

Pool Water Testing Kit..Types Of Test Kits..Swimming Pool

These are the best and are used by most pool techs and professionals.

It does take some time to build up your pool's CYA level and is subject to a variety of changes. Evaporation will mean adding more water which can reduce the amount of cyanuric acid in the swimming pool.

About 2 weeks for the CYA to get between 20ppm - 40ppm is not far off. Keep your chlorine level between 1.5ppm - 3.5ppm and you'll be fine.

You can keep on solar cover on the swimming pool as this will not only help in heating the pool quicker, it will also help with evaporation and lessen the pool chemical use.

Using a heater is fine but remember the hotter the temperatures, the lesser value the chlorine has because heat eats up pool chlorine very quickly.

Hope this helps and best of luck with your pool

Robert