Final answer:
Chlorine sanitizing solutions should be changed when they no longer meet the required sanitizing strength, typically every few hours, tested with a strip. For a 5,000 gal pool to achieve a chlorine concentration of 3.0 ppm, approximately 56.8 grams of chlorine would be needed.
Step-by-step explanation:
The question about when a chlorine sanitizing solution should be changed doesn't have a one-size-fits-all answer, as it depends on various factors including the level of contamination, amount of use, and specific guidelines set by regulatory bodies or manufacturers.
However, as a general practice in food safety, a chlorine sanitizing solution should be checked every few hours to ensure the proper chlorine concentration is maintained, typically between 50 to 100 ppm (parts per million) for surface sanitizing.
The solution should be changed whenever it does not meet the required sanitizing strength, which can be determined using a test strip. Moreover, in settings like swimming pools, the chlorine levels are monitored continuously and adjusted as needed rather than changed at specific time intervals.
For a typical 5,000 gal pool that contains 21,200 kg of water, to achieve a chlorine concentration of 3.0 ppm, we would need to add a mass of chlorine that will result in the desired concentration. One ppm is equivalent to 1 milligram of a substance per liter of water. Therefore, we calculate the total mass of chlorine required using the formula:
Mass of chlorine = Volume of water (in liters) × Desired chlorine concentration (in ppm) Firstly, convert gallons to liters (1 gallon = 3.78541 liters), and then multiply by the required concentration: 5,000 gallons × 3.78541 L/gallon × 3.0 mg/L = 56,814.15 mg or approximately 56.8 grams
This calculation shows that approximately 56.8 grams of chlorine would be required to reach a chlorine concentration of 3.0 ppm in a 5,000 gallon pool.