Scale in a salt water pool (first post)

[allanlaw]

This is a 25-year old 18k gallon pool, upgraded two years ago with a VERY dark Pebbletec finish and salt water system. We are getting a lot of scale on the Pebbletec, very noticeable because of the color. It will come off with an acid wash, but I would like to keep it off. Suggestions.

[PoolDoc]

Sounds like you've got an excessive saturation index (calcium + alkalinity + pH too high)

#1 - Order a K2006 test kit; you can use the Amazon link in my signature if you like. Do NOT get a K2005 by accident. It would be fine for this issue, but once you began trying to do your chlorine correctly, you'll need the K2006.

#2 - Post full results, here once you get the kit.

#3 - Meanwhile, get a cheap OTO / phenol red kit, and use it to adjust your pH till its around 7.0 (no lower!)