CYA conundrum

[mark71]

I have a cyanuric acid puzzle that has been bothering me for a while. Hopefully someone can help...

First, the background: Bought a house last year with a small (7,500 gallon) pool. I spoke with the (former) pool guy who used to "maintain" the pool, and he readily admitted to dumping pucks in the skimmer for probably the past 5 years. Upon testing, I found (not surprisingly) that the cya was off the charts.

With the pool surfaces looking in pretty rough shape, I decided to have the pool replastered and retiled. I also had all above-ground plumbing replaced, including new cartridge filters.

Upon start-up, stabilized tablets were added to get the cya up to a reasonable level for Texas (about 50 ppm). I used cal hypo to maintain chlorine levels -- no stabilized tablets were added for the past 8 months or so.

So here's the conundrum: Even with no additional stabilized chlorine added to the pool, cya has been creeping up and is now at 100 ppm (according to my Taylor test kit). The good news is the pool is absolutely sparkling and easy for me to maintain by adding liquid chlorine every day (I read up on Pool School and stopped using cal hypo because the calcium hardness was nearly 500 ppm). The pool gets light usage on the weekends only.

Should I care about a high (and slowly rising) cya level or just leave well enough alone?
Also, what is causing cya to rise? Is it residue from the plumbing system?

 

[JasonLion]

The CYA has to be coming from somewhere. It would be good if you could figure out where.

CYA is never in municipal water, and almost never in well water. What chemicals do you use with the pool?

 

[mark71]

I have been using Clorox, muriatic acid, Jack's Magic Magenta and JM All Fixed Up.
Recently I stopped using the JM stuff and switched to another clarifier (can't remember the name offhand). But that's it.

I did look in the (new) chlorinator and saw some residue in there, but the chlorinator has been turned off (with no pucks) since start-up.

 

[Richard320]

I wonder if the CYA reagent went bad or something?

 

[mark71]

I got the Taylor test kit very recently.
I am comparing that reading (100) with prior readings I got from test strips and the pool service that did the replastering/start-up/maintenance for the past 8 months.
What's weird is that the pool got 1.5-2 inches of rain last week and the cya was still at 100 when I tested it.

 

[Richard320]

I got the Taylor test kit very recently.
I am comparing that reading (100) with prior readings I got from test strips and the pool service that did the replastering/start-up/maintenance for the past 8 months.
What's weird is that the pool got 1.5-2 inches of rain last week and the cya was still at 100 when I tested it.

Aha! We have a clue!

I'd believe the 100. Test strips are awful, and most "professionals" use them. And I'll bet they "shock" your pool every week with dichlor. That's how it got so high.

 

[mark71]

I'll monitor it closely from now on using the test kit. 100 ppm is the official starting point.

So you don't believe that cya can leach from the pipes over time?
And should I care that cya is relatively high?

 

[Isaac-1]

We generally consider a CYA of over about 90 unmaintainable in the long run, in the short term if you stay on top of your levels and never have a incident (like storm debris in the pool) it is manageable, but I would highly suggest a partial water replacement to get your CYA down to a reasonable number before the heat of summer hits.

 

[duraleigh]

So you don't believe that cya can leach from the pipes over time?
And should I care that cya is relatively high?

Not 50 ppm. No chance.

You should absolutely care. Dealing with high CYA is one of the biggest problems we see on this forum. A drain to get your CYA down to 50 ppm is the best move you can make to keep your pool clear this summer.

 

[frustratedpoolmom]

When I found TFP in 2007 (screenname came from somewhere) my test kit revealed a result of 140 for CYA. My strips had consistently read 30-50. Pool store - 70ish, 80 ish, if they tested - and they even told me once, when I asked why they didn't test it "You don't need to worry about that."