Corrosive water damage to plaster

jwrankin71

Member
Sep 10, 2021
5
29568
Pool Size
15000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Hi all, new gunite pool here that was plastered back in May of this year. PB said to only brush once a week so that's what we did - even though everyone else said twice a day. We had plaster dust for about a month thsn it settled.

Recently, the plaster dust has come back when I'm brushing. I believe some damage occurred when I let the total alkalinity get too low and SI went negative for a few days.

Now, even when brushing the same spot over and over again, I get continuous clouds even though I've got the chemistry back in check. Should I keep brushing until it clears up?

FC 4.5
CC 0
TA 83 (after adjusting for CYA)
CYA 40
pH 7.5
temp 82 F
CH 300
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,817
Texas, San Antonio/Marion, South-Central Area
Pool Size
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Surface
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Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Welcome to TFP! :wave: Before we make too many assumptions, please update your signature with all your pool and equipment details. Also include which test kit you used to get those results. That will be very important in our discussions.

 

jwrankin71

Member
Sep 10, 2021
5
29568
Pool Size
15000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Welcome to TFP! :wave: Before we make too many assumptions, please update your signature with all your pool and equipment details. Also include which test kit you used to get those results. That will be very important in our discussions.

thanks for the heads up, think I got it in there now. Using a Taylor K2006 test kit.
 
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Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,817
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Great. So your numbers as of today aren't that bad at all. Using the PoolMath APP it appears your CSI is slightly negative which is good at this point. Since you didn't brush very much after the initial plaster job, it's very possible calcium dust attached itself to the surfaces and now the lower CSI is releasing that calcium dust. I would continue with regular brushing, but not focus too much on just one area. Keep the brushing consistent across the entire shell. Your plaster work should still be under warranty, so if you have a growing concern about just one particular area, that would be a good time to have your contractor come back out and look at the plaster work.
 

xtexan86

Well-known member
May 3, 2021
54
Fairfield, CA
Great. So your numbers as of today aren't that bad at all. Using the PoolMath APP it appears your CSI is slightly negative which is good at this point. Since you didn't brush very much after the initial plaster job, it's very possible calcium dust attached itself to the surfaces and now the lower CSI is releasing that calcium dust. I would continue with regular brushing, but not focus too much on just one area. Keep the brushing consistent across the entire shell. Your plaster work should still be under warranty, so if you have a growing concern about just one particular area, that would be a good time to have your contractor come back out and look at the plaster work.
Hi, just how long should new plaster be releasing calcium? I've got color fading problems (see different post here from me) where I've lost the blue pigment on the surface. About 2 weeks before I really noticed the gradual color change, pool tech guy had dumped excess acid in pool. Had black stain on baja shelf under water jet and saw what looked like black mold all over the pool, which was just the newly exposed black aggregate (DiamondBrite quartz aggregate plaster). Been dealing with this since June, service tech supervisor was able to remove stain and has been trying slight altercations with water chemistry to try to reveal more blue. Anyway, when he was here yesterday, he did 2 tests on the calcium level and came back with ranges in the 600-700 ppm range. I took a sample down to Leslie's the same day and their result was 339 ppm. Got diamond-infused sanding blocks today and sanded an area. What is revealed is a midnight blue where the original color was more of a medium blue. Service tech supervisor says he's never seen this before and plaster guy swears the acid was responsible so I can't "blame" either one because it seems the only way for the blue to leach out is due to non-colorfast pigment. Supervisor says I'll never get the plaster manufacturer (SGM) to admit what they put in their pool plaster mixes. I was hoping sanding would just reveal the original plaster color but why does it only reveal a much, much darker color? Thanks!
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,817
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Your situation goes a bit beyond my expertise. I'd like to see if @onBalance might have some insight. But I will say this though ... you MUST start testing your own water. You simply cannot rely on the pool store or others for reliable testing. A TF-100 or Taylor K-2006C test kit is a must.
 

xtexan86

Well-known member
May 3, 2021
54
Fairfield, CA
Your situation goes a bit beyond my expertise. I'd like to see if @onBalance might have some insight. But I will say this though ... you MUST start testing your own water. You simply cannot rely on the pool store or others for reliable testing. A TF-100 or Taylor K-2006C test kit is a must.
Thanks for the test kit suggestions and that is on the to-do list. I just want to add if @onBalance reads this the area I sanded yesterday has developed a whitish, slimy film on it overnight. Wondering if that's just more calcium being released or what?
 
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