How much sodium thiosulfate is needed to impact chlorine levels by 10 ppm in 10,000 gallons?

To determine how much sodium thiosulfate is needed to reduce chlorine levels by 10 parts per million (ppm) in a body of water, you need to consider the relationship between the volume of water and the amount of sodium thiosulfate required for dechlorination.

Sodium thiosulfate acts as a reducing agent, specifically targeting chlorine. For typical calculations, you can refer to established guidelines or manufacturer recommendations. Often, it's stated that about 1.5 ounces of sodium thiosulfate per 10,000 gallons of water can lower chlorine levels by approximately 1 ppm. Consequently, to achieve a reduction of 10 ppm, you would multiply this amount by 10.

Thus, using this guideline, 1.5 ounces for 1 ppm means that for 10 ppm, you would need 15 ounces of sodium thiosulfate (1.5 oz x 10 ppm). Therefore, the choice that reflects this calculation aligns with the correct application of chemistry in water treatment practices for swimming pools.

This method of calculating the amount needed to adjust chemical levels based on specific volumes and ppm changes is crucial for proper pool maintenance, ensuring safety and comfort for users.