CYA dropped to below 30

[JesseSchmidt]

That sounds like a leak. If that is the case and you are refilling with tap water (CYA of 0) that would explain your slow loss.

That's what I originally thought too but putting the solar cover on the pool lowered the loss to a minimum and the bucket test showed it was evaporation.

I think I'm going to do a test to see about the evaporation/loss of CYA. If evaporation doesn't take the CYA with it then I'll just chock it up to variation in testing.

 

[sigep739]

That sounds like a leak. If that is the case and you are refilling with tap water (CYA of 0) that would explain your slow loss.

It does kind of sound like a leak. I have a similar issue as the OP. But after thinking more about this thread, made me think that CH would probably go down as well with a leak. Or alkalinity. Personally, I haven't had any of those decrease at all

 

[Lrinaldo99]

Mine dropped from 80 to 50. Pool is in the full sun, but we did have to replace some water because of a leak.

 

[denniswiseman]

I can add I've done zero back washes.

Also, I finally test my CH. It was 250 ppm when cya was 50 and 2 months later is still 250 ppm.

That would have gone down had I backwashed a few times. (it has in the past)

So I definitely have some odd condition where my pool consumes 30 ppm of cya every 2 months.

I have always used the 4lb container of chlorox stabilizer granules on amazon.
This is my first season with this pool.

Figured I would just post this all here instead of a new thread since most
of us here have the mystery of cya going down.

If your fill water is 250 CH you won't notice any difference whereas the fill water has no CYA and you will notice a difference

 

[drywall guy]

Same thing here...lost 10 ppm cya.
Last tested cya on june 16th and was at 30 ppm
Tested last night July 17th and was 20 ppm
Sock is infront of the return now.

 

[BobbyR]

If CYA levels actually do drop over time in some situations or settings, that might explain how some people seem to be able to use pucks indefinitely with no issues. I have a couple of friends who just use pucks with no problem. They backwash occasionally but not to purge CYA and they have clean and clear water. I've never understood how it's possible. It never worked for me when I was using chlorine pucks in my first pool and just following the Pool Store recommendations.

 

[sigep739]

If CYA levels actually do drop over time in some situations or settings, that might explain how some people seem to be able to use pucks indefinitely with no issues. I have a couple of friends who just use pucks with no problem. They backwash occasionally but not to purge CYA and they have clean and clear water. I've never understood how it's possible. It never worked for me when I was using chlorine pucks in my first pool and just following the Pool Store recommendations.

I'm not a scientist, but I sort of buy into the degradation. But the more I think of it, I believe that my pool guy (before I found this website) who was using liquid chlorine (ONCE A WEEK!) measured the CYA incorrectly. I could see how viewing is confusing... and I am pretty sure that the 22 year old guy doing my pool had no idea what he was doing. I was constantly getting algae as a result of only WEEKLY chlorine adds. When I measured mid-June, I was stuck at whether it was "65" (not a true number) or 80... but I only chose 80 as my CYA because that is what the pool guy said mid-May. However, I am now betting that my CYA was somewhere between "65" and 70, and when I checked it was "65"... and I have had two very large pool parties that I am willing to bet had enough splash out to drop 10ppm... as well as several days over 105 and water temps at 90 (degradation?).

Anyway, this all has led me to believe it was a combo of mostly inaccurate reads and splash out along with *some* degradation.

That said - I think you could use pucks for years and years without having any issues... unless you're using pucks with Calcium... but most use the ones with CYA. The risk most people talk about here is that if you ever get algae, you are in for a tough time cleaning it up and likely some draining.

 

[pooldv]

CYA does degrade in pools, typically at a rate of 2-3 ppm per month, up to 5 ppm in higher temps This can also be a bit higher with high FC during a SLAM.

 

[bjbarlowe]

Just to give an update on this. I got my reagent and tested twice the other day to confirm my CYA level is below 30ppm. Last night, I switched to 1-inch trichlor tabs that I had on hand from a previous owner. I hate working with that stuff (always makes me sneeze), but I figured I may as well use it since I had it on hand and I need to raise CYA.

Since I do need to backwash every so often and I get a lot of rain, I'll have to plan to test for CYA more often going forward.

Edit 7/9/18: Blegh, never using trichlor again. It got my CYA up, but threw my PH completely out of whack. I'm used to having zero problems with PH using only bleach. From now on, I'm adding CYA with straight stabilizer.