We are in Austin and the weather has been unseasonably warm, so I decided to warm the pool a bit a start the swim season. After doing a filter clean and testing chems (nothing was needed; all in great shape) I cranked up the run time to 12 hours a day. After a few days, this mysterious white stuff was found in the hot tub and on the tanning ledge by the bubbler. Not salt (yes I tasted it). It's flaky and doesn't dissolve. Calcium Hardness test was 220ppm. Any ideas? Should I be concerned? Thank you as always!