Blue/Green Staining Tubs Only pH=7.0??
A little background. Had new Kinetico 2060S softener and 2100 OD Neutralizer system installed in Oct 2011 with the help of this forum. Dealer came back to make some adjustments etc. Total hardness has stayed at 0 GPG per my test strips and 7.0 pH per other test strips. I had staining before the softener was replaced (Fleck previously), and the Kinetico has helped decrease it, however, I still get staining in 2 upstairs tubs only. Takes 2-3 weeks from a clean tub to see the stains...More background, I have a boiler-mate hot water system. Oil boiler with elec hot water tank. Cirulator on Hot water tank circulates water thru boiler...When I had the boiler replaced (due to leak ironically) 2 years ago, plumber took out what looked like a filter housing. Upon further reading, I think it may have been a polyphosphate feeder on the cold water feed.
Questions: If staining is not caused by low pH, what can it be caused by?
What is a possible solution?
Thanks for the help..