I was hoping for suggestions to look for culprits so thank you kiss4afrog.
I have brushed banding on steps every time I brush, both top and bottom and nothing comes out. I know this is a hiding place as it has had algae there before.
Thought this morning I would get IN and take a hand brush to that band just to be certain.
I did a thorough on my ladder last week. I thought it was clean already and it was except for slight red dirt look inside the bumpers that go on metal, up against the pool wall.
I coated the whole thing AGAIN in bleach including the rubber bumpers inside and out.
I do have a built in light which was totally replace a few years ago so not terribly old. I also scrub it well with each brushing and this morning laid down and took a hand brush to it. Nothing came out around any of the crevices.
I did a scrubbing of the skimmer and face plate with a toothbrush last week. I did find a little algae hiding at that time right inside and around the face plate.
I also took the tooth brush to the jets and another closed off "hole" in the wall that was for an old shark the previous owners had. Nothing around them to speak of. One had a little gray residue fluff off. Others nothing.
I even thought about the tubing in my ladder possibly siphoning old water from the holes it is secured in, in the concrete. Only one of those holds water, the other is dry. But the bad water would have to go up to the arch of the hand rail and then down to the pool and out past the bumpers, which plug the bottom opening. I don't think it could siphon all the way up that arch.
At this point I just don't know. Nobody swimming since Thursday of last week, numbers kept up pretty good I think, and the water has always been crystal clear.
Thank you for brainstorming and helping me. I really do appreciate it and encourage more!
Off to test again.
Joan