CYA is gone

[red-beard]

OK, I've been remiss in checking my levels. Last time I checked CYA was Aug 12th.
Today I was doing some checks before leaving on a trip. Water temp is 51F and the SWG is in "cold" mode (Hayward produces to ~50F). With it being off, I decided to do a basic run on my tests. FC is 8.0, pH is 8.2. Hmm. Better check CYA.
Nothing. Maybe too cold. Warmed up a sample. Nothing. Well, it is below 30 anyway. Chlorine is holding up, so it can't actually be zero.
I know there is a bacteria that is supposed to eat CYA. I just haven't encountered such a drop over the winter.
Thoughts?

 

[mknauss]

Not surprising. Rain overflow, degradation, etc. Add 10 ppm worth of CYA granules and check again in a week or so. If you can then read the level, manage pool that way until later in spring and raise to 70 ppm.

 

[red-beard]

Not sure about the rain. Salt level is still around 3000. Does someone have a link on the bacterial degradation? I know it is supposed to happen, I just never saw it do this much! Of course, I've mostly been fighting too high CYA over the years, until finding TFP

 

[JoyfulNoise]

If it were bacteria the end product would be ammonia and you’d have zero FC. Your FC is 8ppm which would kill the bacteria in question. It’s not bacterial, it’s chemical. It happens. My pool can easily lose 10–15ppm/month and I usually come out of the winter stretch with a CYA around 50 after the summer high in August of 90.

Just chalk it up to loss and move on. Use a floater with tabs while you’re gone.

 

[red-beard]

Use tabs? In a trouble free pool?

I'm actually considering doing that. I need to dig around and see if I have any. Since I'm planning to do the AA stain treatment, I may just let it go the 3 days I'm gone. Water is 50. I doubt I'll get an algae bloom. And my Jack's Purple should be here.