Trouble with cya

[swilk]

Salt water vinyl liner pool....last year I started having trouble maintaining my chlorine level. Every few days I was having to increase my run percentage on my salt cell to keep up. I figured I just had a cell beginning to go bad until I noticed the liner beginning to fade. Scramble mode kicked in and the last thing I checked was CYA. It came back 0.....

I had always read the only way to get rid of CYA was to change the water. Well, I started with a reading of 80 and very rarely add water to my pool.

I added more CYA and brought the level back up to 70.

I just opened my pool 2 days ago....crystal clear water after running for 2 days.

Water temp is 54.

I checked the CYA and it came back 0 again.

What the heck is going on?

I don't drain my pool in the winter and did not add a drop of water when I opened it.

I have a TFP test kit I am using.

 

[smforte]

Dd you get a lot of rain? Also did you test cya at room temp? Give that a try first.

 

[JoyfulNoise]

The CYA test should only be performed on water samples that have been allowed to come up to room temperature (above 68F).

I know this sounds like a dumb comment, but are you reading the view tube correctly? It's 100ppm at the bottom and 30ppm at the top.

Also, do you have a CYA 50ppm standard solution you can test your reagents against?

Just trying to eliminate the obvious...


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006

 

[duraleigh]

Do you have an auto-fill?

You don't include any dates. What was the time period between when you tested and got 70 ppm and then 0 ppm?

 

[kywildcats]

So you get water out of pool and take it in the house to warm to 68 degrees before doing CYA test??

 

[JoyfulNoise]

So you get water out of pool and take it in the house to warm to 68 degrees before doing CYA test??

Yep. The CYA test should always be done with room temp water to ensure accuracy.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006

 

[swilk]

I tested twice today....first time I took water straight from the pool and tested it. The second test I waited with the water in the mix bottle for several minutes to let the water warm up. I do not know the temperature at the time of the test though.

I do not have a 50 test mix to verify against....

As for rain....with the auto cover not much gets in. I've not added to nor drained a significant amount of water since last year.

Reading the tube according to directions.

How sensitive is it to temp? Would it not read anything if the water was too cold?

Last year this problem occurred in late summer.....

 

[kywildcats]

Yep. The CYA test should always be done with room temp water to ensure accuracy.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006[/QUOTE

Is OK to set for a few hours while coming up to temp? Time don't hurt the reading?

 

[swilk]

Do you have an auto-fill?

You don't include any dates. What was the time period between when you tested and got 70 ppm and then 0 ppm?

No auto fill.

Last August for the 70PPM test and today for the 0.

 

[JoyfulNoise]

Mix for 30sec (gentle inversions not vigorous shaking). Rest for 30secs. Then one more inversion and test?

Yes, temp is important but I don't think it will totally ruin the test, just slow the reaction down and possible affect particulate size.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006

 

[kywildcats]

Ok. Thank you!!
I have some of the CYA reagent and a couple more reagents coming for my TF100 test kit tomorrow. I'm going to recheck in a little while, when I get home.

 

[Texas Splash]

Swilk, you won't get much better advice than that from Matt (JoyfulNoise), so I reluctantly chime-in just to re-cap one angle on this. We know CYA will disappear due to the following:
-- Water exchange (ruled-out)
-- Bad batch of stabilizer (has been known to happen on occasion)
-- FC got so low that ammonia kicked-in and eliminated the CYA (possible over the winter?)

Even with the whole temperature variance thing, I would think there should be some CYA in there. If not, perhaps we need to rule-out ammonia as follows:
1. Begin a SLAM and dose FC up to SLAM level. Do not add additional CYA at this point.
2. Retest FC at 10-minute intervals.
a. If FC loss is greater than 50%, add FC to bring back up to SLAM level and continue retesting FC @ 10-minute intervals.
b. IF FC loss is 50% or less, add FC to bring back up to SLAM level. Go to Step 3.
3. If CYA is below 30 ppm, add enough CYA to bring level up to 30 ppm.
4. Continue SLAM as directed in the SLAM article until the SLAM Criteria of Done are met. Test as directed in the SLAM article - no longer need to test FC at 10 minute increments at this point.

Swilk, don't do this ammonia test yet. I'm just tossing it into the mix for consideration. Let Matt continue to work with you and he'll advise if that should be done. This way you don't get too overwhelmed with us hitting you from every direction all at once.

 

[otter86753]

I can't find the threads (my pollen covered brain won't let me think), but there was discussion last year about losing CYA. I had a similar issue as did several others. I wish I could search for them, but translating through four languages and swimming through jello is consuming all my energy today

 

[borjis]

If you lost all of your CYA over winter...sometimes that happens.

 

[swilk]

Maybe I lost it all last winter as well and fought the problem all summer long without realizing it ....

At least I caught it as early as possible this year.

I will take a new sample test .... bringing it into the house for a few hours to raise the temperature before doing the test. Whatever it comes back as I will add the necessary amount of CYA to the pool and test again in a couple of days.

- - - Updated - - -

I was honestly under the impression that the only way CYA goes away is by replacing the water .... that is the reason I was not more diligent with the test. Knowing different now I will make sure and perform the test occasionally throughout the year as well as when opening and when closing the pool each year.

 

[Texas Splash]

It happens quite a bit in regions where folks close their pool and FC runs-out. But still, I'm not sure if Matt (JoyfulNoise) has had a chance to catch-up to our last couple posts since post # 12. So before you add any more CYA, I would let him come back and review. "If" you end-up having to do the ammonia steps as noted in post #12, you don't want to add CYA until you know for sure the ammonia has been neutralized. Otherwise you'll end-up just feeding that monster.

 

[swilk]

Another thing .... I dont close my pool until late November or early December and I open it pretty early. Even though Im in southern Indiana I let the water get cold enough before closing and open while it is still cold enough to not have any "green" water problems.

I did check the chlorine when I opened it up (before turning on the salt cell) and it was at zero. I turned the cell on for and brought the chlorine up to 6ppm and that is when I tested the CYA.

 

[Texas Splash]

That's good to know. The fact that FC was at zero "may" have triggered an event. Normally though, when ammonia is present, FC disappears "extremely" fast. I mean really fast. So when a pool owner starts the treatment as described I post #12, they require a LOT of bleach to maintain FC long enough to over-take the ammonia. But before we get too far ahead of ourselves, go ahead and do your water samples as you planned after letting it warm-up. Once we have all of your test data back, we'll be able to put it all together and should be able to give you a good road map ahead.

 

[JoyfulNoise]

Normal CYA loss is only, at most, 5ppm per month and that's typically in hot water (think spa hot, ~104F). If the CYA were degraded by bacteria, which in and of itself is somewhat rare, then you'd had an FC demand caused by either biuret or ammonia (you need two distinct types of bacteria to degrade CYA; one converts CYA to biuret and the other converts the biuret to ammonia and nitrates).

So I'm still leaning towards some kind of testing or reagent error. Can you please post a complete set of test results, not just CYA.

Thanks,
Matt

 

[Pooldoctor]

Go to a fish store and get test strips for ammonia. It certainly sounds like this could be your culprit.

CYA can be converted to ammonia during winter months.