I have been engaged in an all-out war with my pool, but am gaining ground. That's the good news! I finally have my son to help me and we were able to remove the steps (ladder outside/stairs inside). They had significant staining on them which I assumed was from the black swamp that I started with. I remember the Vitamin C tablet trick that I have read about so frequently here and voila... in about a second, the stain revealed itself to be iron. I dissolved some tablets in water and it was strong enough to clean the stairs and the powder coated rails.
Does this mean that there is an iron problem now that must be dealt with or just a symptom of me having left the pool get into the condition that it was in by not covering/winterizing? The water does not appear yellow, it is a cloudy gray/green for quite a while now.