I think this is metals staining. It doesn't brush off and appeared out of nowhere in 'streaks' in areas.
FC: 5 (Target)
PH: 7.2 (lowering TA right now which is why it's lower than 7.5)
Borate: N/A (not tested)
Is there any way to remedy this? I think my numbers are doing pretty good other than CH being a little high which is typical for our water I believe (hard water!)