Question about Last Year's Pool Numbers (Before TFP Method) - Spa Plaster Issues

[chris87]

I am new to using the TFP method, and I just had a question about my pool experience from last year. I didn't know about this website until mid-season, so I wasn't following the guidelines. I was fortunate in that I had no algae or water cloudiness. However, I noticed that the plaster in my spa seems to have eroded considerably. It was very smooth, but I realized that by August it had become extremely rough. It appears that the top layer was stripped away, and I'm surprised that this could happen so quickly. I am going to have it re-plastered next year, but I am just wondering if it had something to do with the water chemistry. The pool, for whatever reason, does not appear to have been affected.

I have a 35,000 gallon plaster pool with a SWG and Nature2. This was the chemistry throughout the season: 3.0 FC, 40 CYA, 7.6 PH, 260 CH, 60 TA, 3.4 PPM Salt

Can someone explain those results to me? Would anything there have caused plaster issues? What is the significance of the 3.0 FC with the 40 CYA? I now realize that the CA should have been at least 70. Should I have had only 2 PPM in FC, since the CYA was so low? Could the lower CH also have been an issue?

I appreciate any insight!

 

[frustratedpoolmom]

I think you mean CYA not CA.

Actually what you are describing is calcium scale ON TOP of the plaster. It's caused by high PH . Does it typically spill over or is it independent at all?

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So in the spa, when you have aeration from the jets - if the PH climbs up (which it can do quickly in a spa) it causes the CH to scale up on the walls. You can add a scale remover and lower the ph to 7.2. Keep it there for a couple of weeks, brushing the spa with a SS brush every day and it should dissolve if it is new. You'll need to be able to isolate the spa from the pool though while you are doing this.

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Oh and then you should probably use maintenance doses of sequesterant to keep the scale from reforming.

 

[chris87]

I think you mean CYA not CA.

Actually what you are describing is calcium scale ON TOP of the plaster. It's caused by high PH . Does it typically spill over or is it independent at all?

- - - Updated - - -

So in the spa, when you have aeration from the jets - if the PH climbs up (which it can do quickly in a spa) it causes the CH to scale up on the walls. You can add a scale remover and lower the ph to 7.2. Keep it there for a couple of weeks, brushing the spa with a SS brush every day and it should dissolve if it is new. You'll need to be able to isolate the spa from the pool though while you are doing this.

- - - Updated - - -

Oh and then you should probably use maintenance doses of sequesterant to keep the scale from reforming.

Thanks for your post. I noticed it more on the seats of the spa, but I assume it is on the walls too. I can't remember. I haven't been in yet this year. How can I tell if it's CH? From a visual standpoint, it doesn't look like anything is wrong.

By the way, I did mean CYA! Thanks for noticing that. I fixed it in my original post.