I'm draining my pool (SWG) because over the past 5 years the CH level is finally so far out of whack I have no other real choice. Over the last year I noticed more and more the stains (blue color) and now spotting. They are generally all smooth to the touch, but have a couple dark spots that are raised lumps on the bottom. I've included some pictures now that the pool is draining and I can see them better. They look much worse when dry.
Even with my CH too high to even measure by the end of last year, everything else I was able to keep fairly balanced by keeping an eye on it all the time. Before draining, these are the results.
Could not get a proper result for CH, as it was so high, but over the last couple years its been growing higher and higher from fill water. Two years ago I converted to SWG, and that's when I saw the first minor spots, but maybe that was just a coincidence?
Any ideas on if these are calcium scaling, or something else? There seems to be three different types of stains; large blue color streaking, spots, and raised dark lumps.
I plan to re-fill the pool right away, but if there is anything I can do while empty, I'd like to; such as acid washing any stains that may come up?