Plaster Damage

[Okstate1982]

We were recently gone for a week on vacation and came home to some changes to our pool that we quickly noticed. It’s primarily directly below the spillover for the spa but it seems as though there’s damage in other places as well. It looks as if a layer of the plaster has been removed. What does everyone else think? Pool chemistry before I left was PH 7.4 Alkalinity 100 Ca 260 CYA 40. When we got back the Alkalinity was 70. I used trichlor tabs for chlorine while we were gone. We paid the pool builder to come midweek and check/adjust the water chemistry as needed. I think they added way more acid than they should’ve based on the change in alkalinity. I plan to reach out to the pool builder tomorrow but would be interested to hear some opinions before I contact them.

 

[Rocket J Squirrel]

Welcome to TFP. Do you have any "before" photos? That would help prove your case to the PB.

 

[Okstate1982]

So I talked to the pool builder today. They seem to think there’s scaling around the discolored area and that the discolored area doesn’t have scale because of the spillover (turbulence in the water didn’t allow scale to form there). Keep in mind the area wasn’t there before we left. They went on to say they used their trusty test strips and the ph was 7.2 and the alkalinity was 180. They added 2 gallons of Muriatic acid to bring the alkalinity down (holy cow!) and added 1 lbs of soda ash to bring the ph up. As I mentioned I tested both things before I left with a Taylor kit and the alkalinity was 100 and the ph was 7.4. What would the net PH be with those additions? I’m going to try and get some close up pics of the plaster tonight.

 

[Okstate1982]

I should probably mention our pool is 18000 gallons

 

[mknauss]

Wow. That addition makes no sense.
The acid plummeted the pH. Luckily, if the TA is that high (or at least what you reported earlier) it should recover.

The soda ash was a waste. Not enough to matter.