Thanks for this great tool! I had built something like this myself but much more basic and then found this! While the biggest issue is getting the "correct" 24 hour FC demand as this will change daily, it is a very helpful tool to understand how run time and percentage will affect ppm generation. I have been trying to get mine dialed in since the pool started about 2 months ago, but with recent 3 weeks of 100 degree temperatures with no rain followed by 2 weeks of 80 degrees with daily rain where I had to drain the pool by 2 inches already 3 times, I have been having to make adjustments every week.