Blotchy pool bottom- any hope to fix this?

Feb 17, 2018
22
Houston/TX
#1
I’m starting to get a bit concerned over some light and dark spots (hydration?) in our pool. We did Primera Stone and are hoping they will fade after 30 days of water coverage like our PB says. We are about a week away and I am needless to say skeptical.

I’ve seen some folks shying away from using acid for fear of making things worse. We are just curious if mechanical removal/sanding will help or if this is something we should plan to live with. PB said worst case we drain the pool and fix it. Just curious what you think- is there any hope of this going away?

Thanks!
Deep end L-shaped white mark and blotchy stains

Maui/sea turtle-shaped dark spot in shallow end
 

onBalance

TFP Expert
LifeTime Supporter
Jul 25, 2011
856
Utah
#2
The dark spots will probably lighten over time, however the white discoloration areas are very unlikely to darken over time, and may just get worse.
I suggest draining the pool and the buffing (sanding) those light areas which will re-establish a smooth finish and darken those areas to the original color.
Acid washing is not recommended, and will only darken the color temporarily.
 
Feb 17, 2018
22
Houston/TX
#5
The dark spots will probably lighten over time, however the white discoloration areas are very unlikely to darken over time, and may just get worse.
I suggest draining the pool and the buffing (sanding) those light areas which will re-establish a smooth finish and darken those areas to the original color.
Acid washing is not recommended, and will only darken the color temporarily.
Good to know thanks-

We brush daily (3x first 3 days). PB has been balancing the water and covers it for the first 30 days. I just got my test kit last week and after reading the forum I’m confident I’ll able to fumble through it!

Can they sand it down without draining? They did polish the Primera and it looked great... until a few days after the water was added. Just doesn’t seem to be getting any better.

I suppose holding onto the last payment installation is our best leverage to get it fixed promptly?
 

onBalance

TFP Expert
LifeTime Supporter
Jul 25, 2011
856
Utah
#6
If you aren't happy with the plaster finish, and if you are willing to push hard for a remedy (because you are likely to get some push-back), then we need more information in order to help.
As James asked, what are the current pool water readings for pH, alkalinity, calcium, and CYA?
AND we also need to know what the tap water readings are for the same issues.
Find out if they did an acid wash prior to filling the new plaster job, or any acid treatment process,
Is this a new gunite pool, or a re-plaster job?
To help determine whether this is a calcium scaling problem or of a porous surface, please sand where the surface is white with 100 grit-sandpaper and see how hard it is to remove the whiteness.
Is this a salt pool, and has the salt been added already?
How soon did the white areas at the bottom of pool show up after plastering?
It is very difficult to sand-down without draining.
 
Feb 17, 2018
22
Houston/TX
#7
If you aren't happy with the plaster finish, and if you are willing to push hard for a remedy (because you are likely to get some push-back), then we need more information in order to help.
As James asked, what are the current pool water readings for pH, alkalinity, calcium, and CYA?
AND we also need to know what the tap water readings are for the same issues.
Find out if they did an acid wash prior to filling the new plaster job, or any acid treatment process,
Is this a new gunite pool, or a re-plaster job?
To help determine whether this is a calcium scaling problem or of a porous surface, please sand where the surface is white with 100 grit-sandpaper and see how hard it is to remove the whiteness.
Is this a salt pool, and has the salt been added already?
How soon did the white areas at the bottom of pool show up after plastering?
It is very difficult to sand-down without draining.
I’m on the road today but will post test results of the water tomorrow pm (I’m excited to try my test kit for the first time)

I don’t believe they did any acid wash, but am going on a guess. The coating was laid on Mar 6, they came back on Mar 7 to sand it down and we started filling that day I believe. They did rinse something in the Primera stone before filling. Here’s a photo from Mar 7:



This is a new gunite pool using chlorine. The first photo I took where I noticed staining was 3 days after the plaster was done, which was about half a day after we filled the pool. The photo below has mostly dark splotches on Mar 10, but today there is mostly light/bleached areas in the deep end.



PB doesn’t seem concerned. I have serious doubts!
 

PoolguyinCT

In The Industry
Jul 21, 2014
2,674
Connecticut
#8
Good to know thanks-

We brush daily (3x first 3 days). PB has been balancing the water and covers it for the first 30 days. I just got my test kit last week and after reading the forum I’m confident I’ll able to fumble through it!

Can they sand it down without draining? They did polish the Primera and it looked great... until a few days after the water was added. Just doesn’t seem to be getting any better.

I suppose holding onto the last payment installation is our best leverage to get it fixed promptly?
Check your contract before withholding, final payment may be a warranty contingency.

- just sayin’
Ray
 

santacruzpool

Gold Supporter
Feb 24, 2015
502
Santa Cruz, CA
#10
Our Primera Stone finish was troweled on and after it cured it was acid washed - then it was ground/polished by hand polishers. The acid was pumped into our sewer waste drain. The crew who did our work was pouring the acid on and I could see the a huge vapor cloud as the acid did its job...

Assuming your finish was done the same way it sure seems like something happened between your acid wash and the end of the polish stage to create those big blotchy areas.

Here is a photo of the acid being applied:
 
Feb 17, 2018
22
Houston/TX
#11
Our Primera Stone finish was troweled on and after it cured it was acid washed - then it was ground/polished by hand polishers. The acid was pumped into our sewer waste drain. The crew who did our work was pouring the acid on and I could see the a huge vapor cloud as the acid did its job...

Assuming your finish was done the same way it sure seems like something happened between your acid wash and the end of the polish stage to create those big blotchy areas.

Here is a photo of the acid being applied:
Good to know thanks. I wasn’t here for the polishing and our PB said there was NOT any acid wash.
 
Feb 17, 2018
22
Houston/TX
#12
If you aren't happy with the plaster finish, and if you are willing to push hard for a remedy (because you are likely to get some push-back), then we need more information in order to help.
As James asked, what are the current pool water readings for pH, alkalinity, calcium, and CYA?
AND we also need to know what the tap water readings are for the same issues.
Find out if they did an acid wash prior to filling the new plaster job, or any acid treatment process,
Is this a new gunite pool, or a re-plaster job?
To help determine whether this is a calcium scaling problem or of a porous surface, please sand where the surface is white with 100 grit-sandpaper and see how hard it is to remove the whiteness.
Is this a salt pool, and has the salt been added already?
How soon did the white areas at the bottom of pool show up after plastering?
It is very difficult to sand-down without draining.
I just took my first sample and here goes:

pH 8.0
FC 1.8
CC 0.2 (shouldn’t this be 1.8 + 0.2 = 2.0?)
110 ppm TA
230 CH
40 ppm CYA
1.43 qt Acid demand

Do these seem to be in the ballpark?

I also used an aquacheck strip first and it took about the same readings.