- 1). Measure the amount of chlorine in the pool. This can be done using a commercial testing kit; refer to the test's packaging for instructions. Most involve mixing a sample of the pool's water with a solution that will then change the water's color, allowing you to measure it up against a color chart which should indicate the chlorine content. Ideally, you want to shoot for between 2 and 4 ppm.
- 2). Add sodium thiosulfate to the pool if the chlorine is too high. This can be purchased in large quantities at pool or hardware stores. The amount of chemical to be used depends on how much you wish to decrease the chlorine content and the amount of water in your pool. Chemicals are typically added by placing them directly in the pool or by mixing them in a solution of water first, then adding them. Consult the chemical's packaging for specific instructions. Note that ~2.5 ounces of sodium thiosulfate should make a 1.0 ppm decrease in chlorine content for every 10,000 gallons of water or so.
- 3). Allow the chemical to circulate within the pool for at least 30 hours and then retest the water for chlorine content. If necessary, add more chemical to achieve the ideal range.
- 4). To help dilute the pool water more, siphon some water out of the pool and then replace it with fresh, dechlorinated water.