Significant calcium buildup

Jan 9, 2017
10
LA, CA
#1
The short:
How aggressively can I safely attack a significant calcium buildup?

The long:
I'm in the initial stages of SLAMing my pool to "de-pond" it, and while doing the initial debris removal, I noticed significant calcium buildup. The pH is in excess of 8.0 (probably around 8.2 or so, but don't know for sure since my test kit caps out at 8.0), and TA is around 60ppm. I didn't notice this initially because the water was so dirty, but when I reach in and feel the gunite, it basically feels like a coarse grit sandpaper. Since I can't currently see more than a few inches into the water with any kind of detail, I can't be certain how deep the buildup extends, but I have to assume that it covers the entirety of the plaster. Stainless steel brushing has zero effect, but I had some success carefully scraping a very small section with a flathead screwdriver (since that's what I had in my hand that the time). I can tell that this is going to be a very labor intensive removal process. It is what it is, so I just have to deal with it and chew through it one bite at a time for as long as it takes. That said, I'm looking for the most aggressive approach I can SAFELY take. I'm not about to start gouging the surface using a heavy scraper, but I feel like I'll need something a hair more aggressive than a pumice stone at least to knock down the top layer, then move to the pumice to smooth out what's underneath. Thoughts?

Thanks in advance!
 

duraleigh

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In The Industry
Apr 1, 2007
31,392
Sebring, Florida
#2
My first thought is you would do better to complete the SLAM so you can see what you have. You can perhaps do a no drain acid wash but your SLAM will have to be complete first.
 
OP
OP
N
Jan 9, 2017
10
LA, CA
#3
Yes. Sorry, I should have been clearer. I am going to complete the SLAM first. I'm just trying to plan my next step while working on clearing the algae so I can be ready to attack the calcium once I can see what I'm working with (or against, rather).
 

pooldv

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Aug 10, 2012
24,993
DFW, TX
#4
Yes, let's see what we've got and go from there. Here are some options.

There are 4 options to treating calcium scale. From least aggressive to most aggressive.

Sand with 100grit wet/dry sandpaper
Lower CSI to -0.8 to -0.9 and brush often with a stainless steel brush to s l o w l y dissolve the scale, Pool School - Calcium Scaling
Do a no drain acid bath, The Zero Alkalinity Acid Treatment
Drain the pool and acid wash