There was an existing white spot in a pool we service and I tried scrubbing it with a metal brush thinking it was a calcium deposit. I dove the pool and felt it up close with goggles and there was no build-up but rather it looks like it was flush with the other aggregate. I tried acid-washing it and it made it worse, which makes me think that the original stain was due to a previous company that stained the shell with muriatic acid? I went back in our photo records and the initial stain was already in the pool. Any help would be much appreciated. Can I hire a company to do a small plaster patch job?
I think I burnt a pool shell with muriatic acid
- Thread starter Scott Monette
- Start date
- Jun 22, 2014
- 48,006
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Hello and welcome to TFP! 
It looks like the color was acid washed away doesn't it? Not sure of the various cosmetic remedies available short of removing and reinstalling the pebble or whatever finish is on that pool. I'll tag @onBalance for some expert assistance.
It looks like the color was acid washed away doesn't it? Not sure of the various cosmetic remedies available short of removing and reinstalling the pebble or whatever finish is on that pool. I'll tag @onBalance for some expert assistance.I am not sure what the white discoloration area is, but I would try sanding with 80 Grit Wet&Dry sandpaper. It may take a few minutes of sanding to expose the original color.
Is the pool finish glass beads or pebble? If so, that presents a more difficult remedy, and sanding would probably not work.
Patching would be a mistake and would likely look worse than how it appears now.
Is the pool finish glass beads or pebble? If so, that presents a more difficult remedy, and sanding would probably not work.
Patching would be a mistake and would likely look worse than how it appears now.
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Consider the Japanese belief in Wabi-Sabi. They believe that there is beauty in imperfection.
- Nov 12, 2017
- 11,938
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I stained my pebble when adding liquid CYA. It had separated in the jug (as it does) and when I thought I was dumping in the last of the liquid, I actually dumped in the separated glob of CYA. It sank quickly and permanently stained the finish in the time it took to run and get the pool brush. It's still there, years later. It looks a bit like your stain. Is it within arms reach of the coping? Where it would be if someone poured something in while standing on the deck?
That was the new pebble. In the old plaster, I had a line of a stain running from my vacuum port to the drain. Most likely caused by leaking water from that port during the original fill. When some knuckleheads tried to remove the streak with a sander, they ended up grinding a new, bald patch. That patch looked very similar to your stain. Like they ground the plaster down below the cream. Yours looks a bit like the pebbles are missing. Maybe they were never there, and it wasn't revealed until they did that first acid wash. Anyway, the point of that tale is: it would have been better if left alone.
Yippee calls it Wabi-Sabi. I call it a birth mark. Like all of us, all pools haven 'em. Embrace it (but don't mess with it).
That was the new pebble. In the old plaster, I had a line of a stain running from my vacuum port to the drain. Most likely caused by leaking water from that port during the original fill. When some knuckleheads tried to remove the streak with a sander, they ended up grinding a new, bald patch. That patch looked very similar to your stain. Like they ground the plaster down below the cream. Yours looks a bit like the pebbles are missing. Maybe they were never there, and it wasn't revealed until they did that first acid wash. Anyway, the point of that tale is: it would have been better if left alone.
Yippee calls it Wabi-Sabi. I call it a birth mark. Like all of us, all pools haven 'em. Embrace it (but don't mess with it).