I posted recently about calcium scale. It was recommended that I try getting it off with muriatic acid and a scrubber. I did that, and it actually got off a significant portion, but was kind of a pain, so I tried the bio-dex 300 my pool guy left for me. It is basically a few different acids and some thickening agents to keep it in place.
It worked really well, actually, but some settled in a few spots on my pebble tec (mostly on the shelf, where the pool is shallower), and darkened the plaster between the rocks in those spots before I noticed it had settled. I brushed all the sides immediately when I noticed the first spots to prevent more, but there are still a few.
The darkness looks basically like the plaster did when it was first put in, before it had fully cured. I'm assuming the BD300 ate away some/most of the calcium in those spot, but I'm not sure.
My question is, what can I do? If I had to guess, I'd guess that they're going to fade on their own with time, as the plaster did originally, but do I have other options? My pool guy saw and seemed surprised. He said that an acid wash on the top step should blend it in. I've also emailed Bio-Dex to see if they have any ideas.
I've googled, but haven't found anyone else reporting this. Mostly just ads/pages selling bio see.
Thanks for any advice. I promise I'll listen this time.