Marty, John,
Yeah, I apologize for jumping in without reading the whole thread. Marty, your background knowledge of the water source along with John's observation of no staining on the skimmer sock probably eliminates iron.
So, suspended green in a pool , to my knowledge, is the result of either algae or iron.....copper doesn't manifest like that. Looks like you are back to treating for algae but, like Marty, I am puzzled by your lack of progress. Your FC loss overnight certainly indicates algae as well but I wish your pool would hurry up and start changing color!!!
Stay the course.........I can really think of no other option.