How Do You Calculate Contact Time Disinfectant?

How Do You Calculate Contact Time Disinfectant? Step 1: Time is equal to 5,000 gallons x 0.3 (baffling factor) to get a working contact volume of 1500 gallons (assuming the tank is full to capacity). Divide 1,500 gallons by the peak hourly flow of 15 gallons per minute to get 100 minutes of time available.