For a 500,000-gallon tank needing a 50 mg/L chlorine dosage, how many pounds of 70% HTH are required?

To determine the amount of 70% HTH (calcium hypochlorite) needed for a 500,000-gallon tank with a target chlorine dosage of 50 mg/L, the calculations involve several steps.

First, it is essential to convert the dosage requirement from mg/L to pounds. Since 1 mg/L is equivalent to 1 part per million (ppm) and can also be expressed in terms of weight in a million gallons, we use the relationship:

1 mg/L = 0.00834 lbs/million gallons.

Given that the tank has a volume of 500,000 gallons, we adjust the formula accordingly. The formula to calculate the total pounds of chlorine required is:

Total chlorine needed (lbs) = Dosage (mg/L) × Volume (gallons) × 0.00834 / 1,000,000.

Using the provided data:

• Dosage = 50 mg/L

• Volume = 500,000 gallons

Inserting these values yields:

Total chlorine needed = 50 mg/L × 500,000 gallons × 0.00834 / 1,000,000.

Calculating this gives:

Total chlorine needed = 50 × 500,000 ×