Pamsel, I tried to pm but your box is full, so I will put it down here:

I am not sure the green is from the copper. I think that the high ph and alkalinity are making it hard to get rid of the last of the algae. If the water is green because of the copper, then the copper seems to be in suspension from the sequestering agent. High ph and high chlorine will make stain - so maybe that is what is keeping the water green. From the picture of the step, it doesn't seem to have any stain on it, so if it is copper, then how to get rid of it? I'm thinking that you have to get your ph way down, and your alkalinity down too. I'm not sure if the ascorbic acid would work on the water being green - I never tried it, but it may be a good way to go, because the ascorbic acid will certainly lower your ph and alkalinity. I just don't know - I thought the sequestering agent is supposed to hold the copper in suspension and not turn your water green, and I think there is a difference between a chelating agent and a sequesterant - maybe someone else can chime in with the answer? But If it were me, I would really get the pool acidic and see what happens, also if you cut a leg off a pair of tights and put it in the skimmer basket, it will filter out a lot smaller particles.

I can only imagine how frustrated you must be - keep us informed and please keep asking any questions you may have. This is a puzzle, but it probably has a simple solution - we just have to find it.