Checked my CYA after having to pump out water on several occasions from thunderstorms. The CYA had been consistently in the 50-60 range for the last month or so, but had dropped to around 40. I run the pump from 11am to 5pm, with the SWCG set at 45% . My FC normally stays in the 4 to 6ppm range at those settings. I brought the CYA up to 80, and now my FC is reading 10ppm. Did increasing the CYA decrease the daytime FC consumption that much? I've dropped the SWCG down to 30% to see what happens.

Thanks

Yes, and will extend the life of your swcg! You are losing less fc to the sun so your water can maintain a higher fc...

This has been the first summer since the install, so I'm still learning. I started the season out with the CYA around 70, and it seemed to settle in the 50-60 range. I didn't realize that a 20ppm difference in CYA made that much difference. Guess I was asleep in class when that was covered in Pool School.