Crystal like substance

[databrad]

Hoping someone can help identify or provide guidance on an odd crystal or sand type substance. For the last several weeks/months we have had this odd substance mostly in our spa but can be found in the pool vacuum debris bag. We do have a spillway so it possible it's getting into the pool that way.

I have tried brushing the spa, doing a partial drain hoping it would clean it, using our pool blaster vacuum, the pool service guy used a hammerhead vacuum but it just keeps remaining and returning.

Yesterday I saw excess build up again so I brushed it, used the pool blaster vacuum. I saw more so I drained the spa entirely, brushed and used a shop vacuum to get as much as possible. As I rubbed my hand over the surface more seemed to appear and thought maybe the gunnite/plaster was eroding as the pool is 10 years old.

Pictures attached

Thanks in advance all.

 

[mknauss]

Take some acid and put a drop or two on it. If it fizzes, it is calcium. But I suspect it is aggregate from your plaster.

What are your pool water chemistry results?

 

[databrad]

Any particular type of acid to use? Our pool was down from Feb until June. Chlorine has been pretty high for a while (like 21ppm) but we were chlorinating and shocking it for months to keep the pool half way healthy. ph is normal at 7.9, CYA 122, TA 105 from a week ago.

 

[mknauss]

Muriatic. Like you use in the pool water.
What is the CH of the pool water? How did you get those test results?

 

[databrad]

Ok, no fizzle when testing with the muratic acid. Does that mean it's the pool surface eroding?

 

[mknauss]

Does that mean it's the pool surface eroding?

Yes.

 

[JamesW]

What are all of the chemistry readings?

Have you been tracking the CSI at all from the time the pool was plastered?

 

[databrad]

Unfortunately no. We are the 2nd owners

 

[mknauss]

Do you have your own Test Kits Compared?

 

[JamesW]

The substance is likely to be quartz aggregate from the plaster.

Without knowing the history, it is difficult to know why it is coming out so fast.

It could be from really bad chemistry and/or possibly an aggressive acid wash to improve the appearance of the plaster to help sell the property.

At this point, the best you can do is get the chemistry under control especially the CSI.

Most likely, you will have to plan for a replaster at some point, but you might be able to get several years out of the existing plaster if necessary.

 

[databrad]

Thanks for the input and advice. Will work with the chemistry and pool service. Will likely drain and restart after summer