Well, I have tried crushed asorbic acid tablets on a few stains and it hasn't done much of anything. I basically have 3 types of things going on:

1. The rough areas, mostly on the stairs, which seem almost like sand is encapsulated in scale.
2. Many brown stains around pool. They are shaped like a thin leaf or sliver mostly. They look like metal stains. I put metal free in a couple of weeks ago and it didn't do much if anything.
3. Generally lack-luster plaster. The plaster looks dirty in general. It just isn't the off white color it's supposed to be.

Any ideas on how I should attack this? I inspected a lot of the pool yesterday with goggles. There are a lot of areas, like in the stair corners for example, where it looks like etching (or pitting) took place over the winter but most of the plaster doesn't approach the roughness of the stairs. I'm just not sure what to do about these stains. I'm thinking about treating with asorbic acid just to see what happens.

Any suggestions?

Thanks.