Quote Originally Posted by stateroaddog View Post
Sounds great. I got the Bleach (6%) and supplies as you told me. How much bleach do you put it. I looked at the bleach calculator and another chemical calculator that is listed on the site but it only has me adding approximately 134 oz of 6% bleach. to raise teh FC to 3 PPM. That dosent seem like very much bleach to me. Could you advise if that sounds correct or not?
Actually, it's spot-on. You have 21,500 gallons. 1 gallon (128 oz) of 6% will raise 20,000 gallons 3ppm.

Here's the rule of thumb:

One gallon of bleach (whatever its strength is) will raise 10,000 gallons by that strength--In other words: If you add 1 gallon of 5.25% to 10,000 gallons it raises it 5.25ppm. 1 gallon of 6% raises it 6ppm. etc. So....if you add 1 gallon of 6% to 20,000 it's diluted to half-strength--3ppm. You are just over 20,000 gallons at 21,500 gallons. So....you are just over 1 gallon by 1/2 cup.

See how it works? The Rule of Thumb uses the same formula as the Bleach Calculator, but only at the simplest values: 1 gallon. 10,000 gallons. So you adjust up or down from that.