How to Dilute Chlorine in a Pool

Chlorine is used as a swimming-pool sanitizer to kill algae, bacteria and viruses. It's also used in higher concentrations as a shock treatment to clarify the water and remove residual chlorine that has combined with organic matter and become inactive. Too much free, active chlorine in a pool can cause eye and skin irritation and bleached hair. Follow a consistent program to reduce the level of free chlorine in your pool.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Chlorine test kit Chlorine neutralizer

1. 
   Chlorine test strips

   Use chlorine test strips to determine the free-chlorine concentration. Dip the strip into the pool water and compare its color to the color gradations on the chart provided with the test kit. Acceptable levels range from 1.0 to 3.0 ppm (parts per million).

2. Allow the chlorine to evaporate naturally if you have the time. High concentrations will dissipate overnight, or after a few hours of exposure to sunlight.

3. 
   Sodium thiosulfate chlorine neutralizer

   Add Sodium Sulfite or Sodium Thiosulfate to the water to quickly reduce the chlorine level. Determine the number of ppm by which the free chlorine needs to be changed. Add the reducing agent at the rate recommended by the manufacturer for the volume of water in your pool.

4. Run the pool's pump and filters. Test the chlorine level again after 15 minutes to be sure it's within the 1.0 to 3.0 ppm range.

5. Check the water's pH with test strips. Adjust it with a pH balancer to 7.2 to 7.6 if necessary. Test the chlorine level once more to verify that it's within the acceptable range before entering the pool. If not, fine-tune the concentration by adding chlorine or chlorine reducer.

Tips & Warnings

• Read and follow manufacturers' instructions when adding pool chemicals. Never mix two kinds of chlorine.

Resources

• Information about chlorine's role in pool chemistry