CYA Is Disappearing

[angheller]

Location: Las Vegas
SO last year I discovered TFP. Had CYA at 90 and struggled with algae which was a pain because of all the chlorine I had to go through.
I’ll admit over winter I didn’t really do anything….
Once it started warming up I tested the pool and my CYA was at 50. When I “opened” the pool I added a ton of shock granules because I had it on hand. I’ll say about 12 lbs over the course of a couple days.

About a month later and now my CYA is less than 30 as it wouldn’t even register with my Taylor kit.

Last year when I struggled with the high CYA it seemed like the only way to lower it was by draining the pool which I didn’t do. How am I losing my CYA? How so quickly?

 

[PoolStored]

CYA degrades over time, but that seems like a lot...only 30 days?
How old are your reagents?
Do the test again and follow these instructions:

CYA - Cyanuric Acid Test

Cyanuric acid (CYA) is the chemical name for the product commonly called “pool water stabilizer” … Read more…

www.troublefreepool.com

 

[angheller]

CYA degrades over time, but that seems like a lot...only 30 days?
How old are your reagents?
Do the test again and follow these instructions:

CYA - Cyanuric Acid Test

Cyanuric acid (CYA) is the chemical name for the product commonly called “pool water stabilizer” … Read more…

www.troublefreepool.com

At the end of last season CYA was 90.
I just bought my reagent kit last summer.
I then tested for CYA in April to know where my chlorine needed to be and it was 50. I tested that multiple times because I was shocked it was so much lower. Now today I tested CYA again and at the 30 CYA mark I could still see the dot.

 

[PoolStored]

Did you use the instructions I posted? Did you do it indoors or outdoors?
What is your water temperature?

 

[angheller]

So I had a CYA level of 90 last year. Honestly neglected the pool all winter long. We don’t winterize as we are in Las Vegas. I went months without testing or adding to the water.
Now I go to get the pool set up and I have 30 CYA. Did the process you have described above work? I am about to go load up on chlorine and beat this bacteria or ammonia etc whatever it is.

 

[PoolStored]

You don't have ammonia. Your pH would be low, CYA would be gone and you would have high CC.
For you, CYA naturally degrades 5-10ppm per month...just a natural occurrence. You don't need to load up on chlorine.
You may want to do this test tonight. Link-->Overnight Chlorine Loss Test
You fail, you SLAM. Link-->SLAM Process

 

[mknauss]

How are you testing your pool water chemistry?

 

[angheller]

You don't have ammonia. Your pH would be low, CYA would be gone and you would have high CC.
For you, CYA naturally degrades 5-10ppm per month...just a natural occurrence. You don't need to load up on chlorine.
You may want to do this test tonight. Link-->Overnight Chlorine Loss Test
You fail, you SLAM. Link-->SLAM Process

Yes I tested the cya as described. Regents don’t expire until next year. I guess I’ll just dump in some CYA then but wait until overnight test just in case I need to slam.

 

[angheller]

How are you testing your pool water chemistry?

At home Taylor kit.

 

[mknauss]

At home Taylor kit.

Great -- there are many. Which one?

added a ton of shock granules

How much and what was it?

 

[angheller]

Great -- there are many. Which one?


How much and what was it?

K-2006c
12 lbs of hth shock
That was when I originally made this post.
I had my pool pump go out and some electrical issues which I have now fixed so wanted to get it going and ready now that it is 100 plus outside here.
I am going to do another full round of FC and PH. Any other results you’d like me to post here?

 

[angheller]

This one

 

[mknauss]

If that was 65% Cal Hypo, you added 93 ppm FC; That would likely oxidize some of the CYA. And could harm the plaster if it was not thoroughly brushed for a long time.

 

[mknauss]

A full set of water chemistry data is best to have a starting point.

 

[angheller]

It was not all 12 lbs at once. 4 at a time over the course of a week or so.

 

[mknauss]

You still likely spiked the FC very high.

 

[angheller]

This is the current reading as of now.

 

[angheller]

This is the current reading as of now.

 

[mknauss]

Your pH test is not valid at that level of FC. However we know the pH will rise rapidly with that high TA. As your FC gets close to 10 ppm, start to address the pH and TA.

Let the FC fall as you add some stabilizer. Get the CYA to 50 ppm.

NEVER use cal hypo with our fill water. Your CH will rise rapidly on its own. I use softened water for make up water due to evaporation.

 

[angheller]

Ok so only use cal hypo if filling. I will say it did not dissolve well and I vacuumed it up.
So when do I add the stabilizer? When the chlorine gets to 10 or should I add some now?