I don't really know where to put this since we don't have a "pool restorations" section...
This post is long overdue but I've finally remembered to post and had the time to collect all the pictures! This acid wash was completed two weeks ago and took about a day to drain and clean then 48 hours with the garden hose to fill back up. I've since gotten the chemical levels perfect, however I am collecting a lot of "dust" that's left over from the newly emerged plaster. I'm having to backwash about every two days but that is a small (temporary) price to pay!
I used 21 gallons of acid and several boxes of Washing Soda to neutralize it. I found the pump sprayer method of 50-50 water and acid was far too weak and ended up using a watering can and 100% acid to have any real effect. You'll notice, in the gallery of pictures, an up-close shot of the staining. I don't know what was allowed to happen to this pool but in another situation it could actually have been a kind of neat stained concrete effect.
Anyway, the pictures!
Full album of progress here: