Stains and scaling

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
30,000
Laughlin, NV
First I would suggest you get a proper test kit. See Test Kits Compared. I suggest the TF-100 A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols. If your CH is really that low, it is dissolving your plaster. Scale would not be an issue.

Try to scrape off some of the 'dirt' stains. See if muriatic acid makes it fizz.