Pool Calculator; useful?

[CarlD]

Some use it and swear by it. I never do.
I figure 1 gallon of <n>% bleach in 10,000 gallons of water raises FC by <n>ppm. It's a convenient rule of thumb based on the actual formula: (1,000,000/pool vol) * (bleach concentration) * (amount of bleach) = FC increase.

[JimK]

Some use it and swear by it. I never do.
I figure 1 gallon of <n>% bleach in 10,000 gallons of water raises FC by <n>ppm. It's a convenient rule of thumb based on the actual formula: (1,000,000/pool vol) * (bleach concentration) * (amount of bleach) = FC increase.

For those of us who are more mathmatically challenged, could you give an example (perhaps using my 20k gal pool using 6% bleach)?

Thanks.

[Watermom]

In 10,000 gallons of water, a gallon of 6% bleach would add 6ppm of chlorine. So, since you have twice as much water, in your pool, it would add only half that much which would be 3ppm of chlorine.

[AnnaK]

Figuring bleach is pretty easy, but how do you calculate borax or baking soda? I'm one of the mathematically challenged.

[JimK]

In 10,000 gallons of water, a gallon of 6% bleach would add 6ppm of chlorine. So, since you have twice as much water, in your pool, it would add only half that much which would be 3ppm of chlorine.

Thanks. I wasn't clear about parts of the equation, such as the units for the amount of bleach (ounces? gallons?) and the part about concentration (for 6% bleach, would I multiply by 6? or 6%?), but your example clears it up.

[Watermom]

Anna, I never calculate borax and baking soda. I just make a judgement on how much to add and do small increments until the target is reached. There are so many variables that affect pH and TA that it is kinda hard to have an exact formula for them.

[AnnaK]

For pH, I agree, but alkalinity is pretty straight forward.