Plaster is coming off

[Hagerstown]

Hello,

New to pools. We moved into our new home with below ground pool approx 2 months ago. Size of pool is approx 12,000 gallons and has a small connected spa, both with concrete/plaster finish. Pool's is somewhat stained (former algae blooms?), but okay for now. Thought we would have to acid bath or re-plaster sometime next year. I found your website and I am following the BBB method now.

My problem is that small pieces of the plaster are coming off and exposing the concrete(?) underneath. Pieces vary from the size of a quarter for most spots to one spot that is 3inches by 2 inches. The exposed area beneath is rough and if I rub it with my finger it feels like loose particles of aggregate come off. This has been happening over the past 2 months and seems to be getting worse. My fear is that I'm doing something wrong chemically? Maybe it was a bad plaster job? Here are my latest test results:
Water quality looks very good/clear.

FC - 8
CC - 0
TC - 8
PH - 7.8 (using dry acid mixed with water in 5 gallon bucket instead of liquid MA)
T/A - 70
CH - 400+
CYA - 50 (this had been as high as 120, but drained 1/3 of pool water and stopped using the chlorine tablets)
Temp - 64

Thanks!

 

[Melt In The Sun]

Welcome to TFP!
Some pictures would help, but it sounds like you have plaster at the end of it's life. Flaking and exposing the underlying gunite is normal, and means it needs to be replaced. Do you know how old the plaster finish is? There's nothing obviously wrong with your test results (pH is a little high and a definite number for CH would be good), and certainly nothing that would cause this. It's just ordinary aging.

 

[Hagerstown]

I would have to guess that the plaster finish is 11 years old (house remodeled in 1999), and I'll try an upload some pictures later in the week. CH is 400 by my test (this is the hardest test for me, the color shifts more to clear than to red after 40 drops. Leslie Pool Supply listed my pool water at 310 when I had the water tested)

Thanks!

 

[JasonLion]

It is definitely time for new plaster. Lasting 10 or 11 years is more or less normal for plain plaster.

The exposed gunite will leak, but only very very slowly. Other than that, there is no immediate risks to having failing plaster other than it not looking so good.

 

[Hagerstown]

I really appreciate you answering my question. I'll probably wait until the end of summer (So Calif) before new plaster and enjoy the pool for now.