My Intellichlor SWG says I need to add salt. The indicator light only tells me the ppm is less than 2500. I will get a test done on the water to determine the salt level exactly, but is there a formula to tell me how much salt to put in?

For example, my pool is 18' x 36', standard diving pool, so that's about 22,000 gallons I think. If the salt ppm is 2000 how much should I add to get it up to 3000?

Thanks!