Can Pool Chemistry Cause Extreme Chalking of Fiberglass Pool

[etbrown4]

'm working on 2, that right 2 identical fiberglass 15,000 gal inground pools, with extreme chalking problems so bad that they both plug their respective sand filters within 4-6 hours.

Both were clear upon opening last week, but have begun encountering extreme chalking of the gel coats in both.

The pools were fine last season. they are 10 yrs old.

Has anyone experienced this, and if so did you find something in the chemistry that caused it?

Tips appreciated!