waterbear: Spank -> Ouch! -> Got it.

topjobs: Are you confident of that value? I apologize; I presumed the PS had fouled / mis-read the test. Waterbear is right, of course. Is your pH low now? Is there evidence it has been low historically ( an in-line chlorinator, etched surfaces, metal corrosion ). The copper came from somewhere, you may need to look for damaged equipment.