Calcium nodules after new plaster?

Martinmartin

Member
Apr 29, 2015
22
MD
We re-plastered our Maryland pool in late 2019. Used a WetEdge Quartz product (link below).

The pool was winterized shortly after the 'curing' period (~30-45 days after plastering). I brushed the pool and did my best to keep the water chemistry in line with WetEdge's 28 day startup guidelines. I had the service company check the chemistry over the winter (though I don't think they did much or anything).

No major issues after opening in 2020 other than a distinctive watermark line on the plaster (water level was reduced for winterization). The plaster above this line (~12in of plaster before tile) looked whiter/washed out. It was a bit unsightly, but didn't worry me much. See picture below under the tile line - there is a white/hazy band.

Fast forward to 2021 - we just recently opened the pool and I noticed a bunch of white streaks along with a lot of general 'mottling' (not sure if that's accurate). I have also noticed some circular discolorations/defects that look kind of like spiderwebs. Or like circular mottling.

Please see the attached 2 pictures. The 2nd picture is of the deep end vertical wall under the auto-cover tile shelf. White streaks + circular defects can be seen here.

My specific concerns are:
  • White streaks, mostly on vertical walls, but some formations on the floor as well. Calcium nodules?
  • ~12 in white haze under tile from lowering water line
  • Circular "spider web"/mottling defects
  • General 'mottling' (visually, this doesn't bother me much. But I'm concerned it's a sign of an underlying problem)

Appreciate any/all suggestions. This forum is an amazing resource.

FWIW, I used a WaterLink Spin Touch for testing last year (was trying to save time). I've come to realize it's not accurate across the board. I know this because I have been SLAM'g my pool for almost a week trying to get rid of persistent CCs that wouldn't go away. Today I finally broke out the titration TFT kit and measured CCs at 0! Spintouch is still recording ~3.

Pool Facts: Plaster, Maryland, Auto Cover on 99+% of time, SWG. Salt ~3000. Calcium ~250. CYA was generally low (~20-30) because the autocover is almost always on. pH always seems to be high (I was adding muriatic acid weekly last year and pH seemed to be above 7.5 every time I tested). Heat Pump - water temp is generally high 80s/low 90s during summer (per my wife). I was not familiar with CSI until recently, but when I enter my general #s, the result is not close to less than -.6.

FWIW, the original plaster was white. They acid washed but only chipped away around the tile/fixtures/etc. They did not find any delaminated plaster. They brushed on a concrete looking product that apparently helped the new plaster adhere to the old plaster. Then they sprayed/troweled on the WetEdge, then acid washed again, then filled.

One thing I'll note - even though this was plastered 1.5 years ago, we're still getting quite a bit of 'plaster dust'. It never really stopped.

Thanks for your thoughts!


Wet Edge Luna Quartz St Maarten: Wet Edge | Products | St Maarten
 

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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
29,067
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
None of that is your fault. Lots of things going on with your poor plaster installation…




 

Martinmartin

Member
Apr 29, 2015
22
MD
Thank you very much for linking to those references! Good to know next time I go down this path...

We used the pool for the 1st time over the weekend. While I was originally concerned about visual blemishes, after using the pool, now I'm worried about the incredibly rough plaster! (much rougher than last season, which was the 1st full season since we re-plastered in Fall 2019).

Kids had scrapes/cuts on their feet and shins.

Did some research and am guessing this is due to high pH in the offseason. I didn't check the water during the offseason, and when we opened a few weeks ago, initial pH was reading 8.6. Yikes. Added some acid, brought it down to 8.0. Added some more acid, brought it down to 7.2. Now it's back up to 7.5. It has a tendency to go up quickly. Guess this is normal for SWG pools, especially after a new plaster job.

I rubbed a pumice stone on some of the rough patches and they smoothed out. I couldn't tell for sure, but it felt like some of the grit might have been rubbing off just from rubbing my hand against it.

My hope is to improve the situation without the pool being out of service for more than, say, ~ 1 week. Would very much appreciate suggestions.

I'm thinking to start off by bringing pH down to ~7.2 and trying ~2 gallons of 'Scaletec Plus', combined with frequent brushing (maybe even with a steel brush, which I generally don't use). I could manually hit the steps with the pumice stone (for the little kids) as the surface area isn't huge.

One thing I'll point out - ever since we had the plaster redone in Fall 2019, there has been a ton of what I'll call 'plaster dust'. It persisted all last season and is still there this season. The Polaris picks up ~1-2 sizable clumps (about the size of a lacrosse ball) of a heavy sand-like substance every few days (running only ~2 hours per day). Not sure what that is from, but I know it's not good...maybe this is the scale coming off the walls?

Thank you again for your help!!

Current Water Chemistry:
FCL: 4
pH: 7.5
Alk 84
Adjusted Alk: 74
Calcium Hardness: 250
CYA: 32 (I keep this low as we have an autocover that is on 99% of the time)
Salt: 3,000
Phosphates: 1,000 (I'm not treating this at the moment)
 

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
1,218
Utah
Rough scale can be removed by an acid treatment or sanding.
But the more serious issue is the random calcium nodules that are forming all over. You may want to bring this warranty problem up to the plastering contractor because it has to do with the loss of bonding of the new plaster to the base material. Calcium nodules are a symptom of delaminations and/or bonding failures.
 

Martinmartin

Member
Apr 29, 2015
22
MD
Rough scale can be removed by an acid treatment or sanding.
But the more serious issue is the random calcium nodules that are forming all over. You may want to bring this warranty problem up to the plastering contractor because it has to do with the loss of bonding of the new plaster to the base material. Calcium nodules are a symptom of delaminations and/or bonding failures.
Thanks for following up.

Are you referring to a no-drain acid wash? (I'm thinking it's not a good idea to drain the pool due to the calcium nodule issue we're facing)

I may contact the plasterer, but my guess is they will hide behind "we have a 1 year warranty" and/or "this is caused by water chemistry."

Regardless, even if they accepted responsibility (which I think is extremely unlikely), what would I want them to do? What's the fix to this other than chipping out the [now] 2 layers of plaster and starting over?

One thing to note, they did not chip out the old plaster (aside from around fittings). At my insistence, they did acid wash the old plaster (which was not their standard procedure) and then they applied SGM Bond Kote on top of the old plaster.

Any ideas on what the 'sand' substance is that the Polaris is constantly picking up?
 

onBalance

TFP Expert
LifeTime Supporter
In The Industry
Jul 25, 2011
1,218
Utah
A no-drain acid bath will probably work.
It may be legally required to provide more than a 1 year warranty for bond failure.
Yes, all the plaster should be removed and replaced with a new coat of plaster, and done better.
The Polaris is probably picking up scale.
 
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