Chalk-white scale on Fiberglass Saltwater Pool

We have been to every pool place in town, had the pool installer here, and had management from the pool manufacturer come to town, all to help us figure out what is causing the white pool scale to form on our (once beautiful and sparkly ) 5 year old fiberglass shell. We have learned that nobody seems to know what they are talking about and that just about every person we have tried to get help from contradicts each other. We are out of hope and just want to know what to do to try to stop the problem for getting worse. You seem to be the most honest and straightforward place I have been, but after reading all over the website for the last 2 hours or so, haven't seen anything that relates to our issue. I am just looking for a starting place of where to look/read for some guidance.

Thanks so much for any idea of where to start.