OK, try this one...http://www.thepoolcalculator.com/


It shouldn't take more than a day or two in hot sun to bring your chlorine down to swimmable levels. Watch that CC, though, if it goes up (or doesn't go down after a day in the sun), you need to maintain shock level for awhile longer. It will go up and down as a byproduct of people swimming, but if the sun doesn't dispel it, then you're not finished fighting stuff in the water.

Janet