Quote Originally Posted by mas985 View Post
#1 is likely your problem. SWGs can easily scale if the CSI (calcium saturation index) gets too high. You are better off with a slightly negative CSI to keep the scale off. You can use the poolcalculator.com to figure out your current CSI.

Also as cells age, then tend to accumulate more scale. I would avoid scraping the scale since that could also scrape the cell coatings. You are much better off using acid to clean cell then any mechanical method.
Thank you for the information and suggestion on how to clean the cell.

Are you saying that allowing pH to get up to 7.7 is an issue even though its still considered in the normal range? Should I go back to adding acid whenever pH reaches 7.6?

I played around with the pool calculator using a variety of levels in each field my pool might see throughout the season and found the CSI varied between -0.74 and -0.02 (it always came out in the negative).