Refinished existing 20x40 Gunite pool, issues with brown/orange rough surface spots

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G

GunitePool

Member
May 31, 2022
10
Long Island, NY
Pool Size
35000
Surface
Plaster
Chlorine
Liquid Chlorine
Hello,

Attached picture was after completion into the beginning of 2021 summer season. We had the exiting pool redone. which included new pool equipment, pad, plumbing, electric and coping, tile and marble dust. Added a heat pump, prior setup was basic pump/filter.

Closed the pool with clean and clear water. Upon opening the pool this spring, water was green which is typical. We use mesh loop lock that is not 100% sunlight blocking.
I will add photos of what the gunite looked like. At first thought was some type of algae that was foreign to me like a mustard/yellow or something else, but it was not.

seems to be some type of calcium leaching out of the gunite, at least my best guess so far.

Any help with what could of caused this ?
 

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Sounds like the pool developed scale while closed last winter due to the pH rising from the plaster continuing to cure.

Why did you wait until the end of the season to work on the problem. It will be difficult to do anything before closing the pool now.

Post a complete set of test results on the format below and tell us what plaster startup guide you followed and how you have managed your water chemistry.

FC
CC
pH
TA
CH
CYA
SALT
 
ajw22 said:
Sounds like the pool developed scale while closed last winter due to the pH rising from the plaster continuing to cure.

Why did you wait until the end of the season to work on the problem. It will be difficult to do anything before closing the pool now.

Post a complete set of test results on the format below and tell us what plaster startup guide you followed and how you have managed your water chemistry.

FC
CC
pH
TA
CH
CYA
SALT
Click to expand...
i was told only option was draining and acid washing, which I did not want to do
 
GunitePool said:
i was told only option was draining and acid washing, which I did not want to do
Click to expand...

Acid washing will etch the palster, thin it, and reduce the life.

If you started at the beginning of the season you can melt away some of the scale by keeping the water CSI highly negative. That is the opposite of the highly positive CSI that causes scale.

It is better to sand the plaster using diamond sanding pads on a power sander. Plaster installers have that equipment and do that for polished finishes.

@onBalance
 
ajw22 said:
Acid washing will etch the palster, thin it, and reduce the life.

If you started at the beginning of the season you can melt away some of the scale by keeping the water CSI highly negative. That is the opposite of the highly positive CSI that causes scale.

It is better to sand the plaster using diamond sanding pads on a power sander. Plaster installers have that equipment and do that for polished finishes.

@onBalance
Click to expand...
I followed a strict regime during the curing process, we brushed the whole pool daily and maintained chemistry. Unfortunately you are correct kept curing after I closed which was probably early October. The company I used were very unprofessional, They told me it was whoever closed the pools fault and washed their hands of the job. My guess since they delayed completing the job till after fathers day that they added something to slow the curing process to the mix.

I will get the current readouts, when i test water.
 
I suggest you read up on TFP Methods in Pool School

Our methods are different then what you have been following with Leslies.

www.troublefreepool.com

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!
www.troublefreepool.com www.troublefreepool.com
 
Purchase some wet&dry 80 grit sandpaper and try sanding a small area to see what the results are. My guess is that the stained brown areas is dirt and scale combined. If so, then sanding will remove it more effectively than acid washing. It is NOT calcium or anything else leaching out of the gunite. The staining is a deposit on the surface.
 

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Anyone every hear of SCALETEC? I was told to add two 64 oz bottles. then next year dump the water and scape it off gently.
also so something on line about diamond polishing of rough plaster for a smooth finish?
 
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