The B-B-B method is really a simplified, yet more accurate and effective means of maintaining your pool. It's also flat-out easier, cheaper, and less time-consuming. The only down side is all the pool stores and pool service guys lose income!

Here's a short-cut to figure out how much bleach you need: I call it the rule of thumb.

1 gallon of bleach (or liquid chlorine) will add EXACTLY its concentration in PPM to 10,000 gallons. So 1 gallon of 6% will add 6ppm to 10,000 gallons. 1 gallon of 5.25% will add 5.25ppm, and 1 gallon of 12.5% LC will add....12.5ppm.
If you double the amount of water to 20,000 gallons, you need 2 gallons to get the same effect.

Therefore, to raise YOUR pool by 6ppm, you'd need 1 gallon of 6% for the 10,000 gallons, and 1/2 gallon of 6% for the 5,000 gallons, or 1.5 gallons to get 6ppm. Since 1 gallon is 2/3 of 1.5 gallons, and 4 is 2/3 of 6, one gallon of 6% gives you 4ppm. Got it?

1 gal of anything adds its percentage as PPM to 10,000 gallons. (works for liters, too, but only if you measure both the bleach and pool in liters).

Carl