No Cyanuric Acid?

Test results:
FAC 1
TAC 1
Salt 2900
CYA 0
TAC 80
pH 7.4

My question is this, can I really have NO Cyanuric Acid? I was under the impression that this never went away. The reason I'm here asking is because a buddy of mine got burned by adding to much to his pool and he said he had to drain it, something I obviously want to avoid.

The pool is one year old, saltwater, in-ground, and approx 17,500 gallons. When I tested in the fall I had my CYA was 50. The pool is in Texas so I didn't drain it over the winter or anything.

Obviously the chlorine measurements are a bit low, which would be explained by absence of CYA. The pool calculator said I need to add nearly 2 gallons of liquid stabilizer ~240oz was the result I believe. Anyway, do I really need to add that much CYA? As for the pool, its freaking sparkling right now, couldn't be happier. Anyway, eagerly awaiting advice on CYA.

Yes, it's possible you have none.

Some common types of soil bacteria can 'eat' it, and then 'poop' out either ammonia or nitrogen. I'm not sure how you're testing -- 'guess-strips' are never very accurate, and the stabilizer guess-strip test is the worst of them all.

An easy way to confirm no CYA is to
1. turn off your SWCG
2. add 5 ppm of chlorine via bleach (about 1.5 gallons of plain 6% household bleach) in the EVENING.
3. Test in the AM -- if chlorine is low, you have OTHER Problems.
4. Test that evening -- if it's a sunny or partly sunny day, and you have chlorine, you have stabilizer. If you have no stabilizer, you'll have no chlorine at the end of a sunny day.

I test the pool with a test kit, not the bonk strips.

I put in 1.5 ish gallons of bleach last night, plenty of Chlorine this morning. I'll test tonight to see if there is any left. It's gonna be plenty sunny today.

Quote:

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Originally Posted by Strongmad

I test the pool with a test kit, not the bonk strips.

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If you used the 'cloudy water' test for CYA (melamine precipitation), and got a zero result . . . it's zero. The remaining question is, did the CYA go to nitrogen gas (no problem) or ammonia? If it's ammonia, you'll see high combined chlorine levels, and low free chlorine. You have to use a DPD test kit to get good info on that.