I have downloaded and read your "The Complete Guide to Home Chlorination Systems". Thank you! This is an excellent guide. I have a water treatment system for iron that has a chlorine pump, retention tanks, a Big Blue filter, and a Culligan PE tank (a charcoal filter).
Question 1: I am now trying to calculate the correct chlorine solution for my system. The flow rate is 10gpm, Iron is 22ppm,and the chlorine pump rating is 12 gpd. As I understand your guide, the chlorine demand for iron alone would be 22. I am using the formula on page 12 of your guide. To solve for solution strength using a 50% pump meter setting (6 gallons per day), I calculated as follows: 10gpm flow x 22ppm chlorine demand x 1440 divided by 6 gpd pump meter = 52800 ppm chlorine solution. Have I done this correctly?
Question 2 - I am not sure if I calculated the chlorine demand correctly. I have two 120 gallon retention tanks, so with a flow rate of 10 gpm, I have a 24 minute retention time (correct?). How should I use this information to calculate the chlorine demand?"
Colin T.
Dear Colin - these are great questions. Here are the answers:
Question 1: For the formula, if you are using 5% chlorine bleach (which is the same thing as saying 50,000 PPM) you would use this:
10gpm flow x 22ppm chlorine demand x 1440 divided 50,000 = 6.3 Gallons per day of chlorine used
So say you have a metering that can pump 12 gallons per day, you would set the pump output to 50%
For Question 2, if you have a 120 gallon retention tank, and 10 GPM, then you have a 10 minute retention time, which

Also see our online chlorinator calculator:
http://www.cleanwaterstore.com/technical/water-treatment-calculations/sizing-metering-pumps.php