How to Lower the Chlorine Level in a Swimming Pool

Owning a pool is a lot of work. You must constantly monitor the chemical balance of the pool water to prevent bacteria and algae buildup and at the same time ensure the chemical levels do not become harmful to the equipment and yourself. If you’ve tested your pool’s chlorine levels and the chlorine content is higher than it should be, there are a few ways you can reduce this back to acceptable levels.

Things You'll Need

  • Bucket
  • Garden hose
  • Chlorine test kit (DPD Colorimetric test kit)
  • Sodium thiosulfate
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Instructions

    • 1

      Remove the cover of the pool and wait a few days. Chlorine dissipates over time, especially when in direct sunlight. After two or three days, test the chlorine levels again. Test the levels with a DPD Colorimetric Test Kit. Fill the included vial to the indicated level with pool water and add the two testing chemicals, or reagents. The darker the shade of red the water turns, the higher the concentration of chlorine. Keep a careful eye on the color change of the water, as if the pool sample turns a dark red and then back to clear, it is a good indication that there is an excessive amount of chlorine in the pool. Refer to your test kit instruction manual for specific instructions.

    • 2

      Add non-chlorinated water to your pool. Run the hose from the house and add fresh water. If the pool is completely full, use a bucket to remove some of the chlorinated water. Retest the chlorine levels and repeat as needed.

    • 3

      Pour a chlorine neutralizing agent into the pool to counteract the high level of chlorine. Pool supply stores sell chlorine neutralizers, also known as sodium thiosulfate. Mix the neutralizer in a large bucket with fresh water, following the exact instructions included, and pour the solution from the bucket into the pool water. Walk around the perimeter of the pool to disperse the solution, allowing the filtration system and pump to spread the neutralizing agent throughout the pool water. Test the chlorine levels after the solution has had a chance to spread throughout the pool.