What would be the total weight of chlorine needed for disinfection if a 500,000-gallon tank requires 50 mg/L dosage of 70% HTH?

To determine the total weight of chlorine needed for disinfection in a 500,000-gallon tank requiring a dosage of 50 mg/L of 70% HTH, we start by calculating the total amount of chlorine required in milligrams.

First, convert the volume of the tank from gallons to liters, since 1 gallon is approximately 3.78541 liters:

500,000 gallons × 3.78541 L/gallon = 1,893,000 liters.

Next, calculate the total mass of chlorine needed by using the dosage of 50 mg/L:

50 mg/L × 1,893,000 L = 94,650,000 mg of chlorine.

Since we need the weight in pounds, we can convert milligrams to pounds (1 pound = 453,592 mg):

94,650,000 mg ÷ 453,592 mg/pound ≈ 208.55 pounds.

The formulation used is 70% HTH (high test hypochlorite), meaning that only 70% of the weight is effective chlorine. Thus, to find the total weight of HTH required, we divide the effective chlorine mass by the percentage of chlorine:

208.55 pounds ÷ 0.70