Stains and scaling

[Kpareo]

Could anyone help me figure out how to remive dirt stains and rough patches on my pool plaster???

Test shows
FC 10
pH 7.8
Alkalinity 80
Calcium Hardness 75
Phos 300

I don't know where to start. Thanks for any help.

 

[mknauss]

Welcome to the forum!
How did you get those test results? The CH level is very low for a plaster pool. Are you sure that is scale and not the plaster eaten away to the gunite shell?
I suggest you read ABC's of Pool Water Chemistry.

 

[Kpareo]

Leslies did the test.
No, it is not the gunnite.
it is still white plaster. It just has these “dirt” stains.

 

[mknauss]

First I would suggest you get a proper test kit. See Test Kits Compared. I suggest the TF-100 A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols. If your CH is really that low, it is dissolving your plaster. Scale would not be an issue.

Try to scrape off some of the 'dirt' stains. See if muriatic acid makes it fizz.

 

[Kpareo]

Can not scrape it off.
Muriatic acid makes it cloudy not sure if that is “fizz”

 

[Kpareo]

When i test my calcium hardness on strip it shows to be 250...

 

[Kpareo]

I used a test with drops and got hardness at 170...

maybe the guy who did my test didn't know what he was doing???