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I used to think I couldn't swim until my chorine level was below 2.5--lost a lot of days in the pool after shocking. Then I read somewhere it had to be under 4 to swim. More recently I read people recommending running pools at 3-5ppm, or even much higher, depending on CYA levels. Of course, you can't monitor that with a Walmart test kit. But even if I get the $75 kit, is it safe to swim in water with high chlorine levels?

 

Andy

There has been little research into the health effects of low levels of chlorine such as is found in swimming pools.  The main problems in pools is the disinfectant byproducts which actually should go down as the chlorine levels get higher.  I'm not sure that there is ever a reason to operate over 10 ppm and I feel comfortable with chlorine levels below that.

 Your comments about cyanuric acid (CYA) levels do require some comment.  You are right that chlorine levels need to be higher at high CYA levels.  However, at some point even high levels of chorine won't disinfect your pool in a timely manner.  CYA should be tested and maintained below 50 ppm if possible.  Considering a chlorine product that is not stabilized and just adding CYA in the spring may save you a lot of hassle and improve water quality.  I would add about 20-25 ppm CYA to the pool in the spring, operate using a non-stabilized chlorine product and get the best of the stabilizing from the CYA without the downside.  Backwashing and splashout will lower the CYA level a little by fall, but not enough to worry about.  Best of all, you are closely controlling the CYA and shouldn't have to test for it.  Besides, levels below 30 ppm are very effective but are below the ability of the test kit to test.

 Steve Keifer

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Steve Keifer

Agreed with Steve. Good clean, well balanced water with no combined chlorine and even at 5ppm it would not be very noticeable.