This doesn't sound like scale which would by white and not clear, but if you post your numbers on closing then that might help. In an SWG pool, there is a strong tendency for the pH to rise (due to the aeration from the hydrogen gas bubbles produced in the SWG) so if the SWG were kept running and there wasn't any acid being added to the pool to lower the pH, then a high pH would lead to scaling which is the precipitation of calcium carbonate. Was the SWG running over the winter after the pool was covered?The specific numbers that are needed are pH, Total Alkalinity (TA), Calcium Hardness (CH) and Cyanuric Acid (CYA). I assume with the SWG that the salt level is around 3000 ppm, but if you know differently then you can post that as well. If you know the temperature, that's also helpful.
Chem Geek,
Thanks for the post. Sorry for not getting back right away. I had some password difficulty with the site. I will post my closing numbers as soon as I can.
For now the SWG was not running over the winter. and the pool was covered.