Confused by CYA Test Results.

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Sactojay916

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Dec 22, 2012
10
Hello all,

New to the forums, but I've been reading since I was in contract in December on my home that just so happened to have a pool. Now that I own it, I'm trying to tackle the pool chemistry.

I ordered the TFT100 kit right away with the speed stir.

The home came with a boatload of Leslie's pool supplies conditioners, triclor pucks, muriatic acid, and algaecides.

After reading these forums, I quickly learned of the perils of the pucks and the CYA Correlation.

However, my first reading results were quite confusing.

PH 7.5
FC Less than .5
CC .5
TA 50
CAL 160
CYA 0????

The CYA solution with pool water was crystal clear. However, knowing that pucks add CYA, this can't be right.

I added 2 gallons of 10% liquid chlorine, and re-tested the next day.

I got
Ph 7.3
CC 1.5
TA 50
CYA still 0

Then today I tested again, and the CC dropped back down to .5 which makes me think that maybe I don't have any CYA? This time I warmed the temperature of the water up to room temp, and even let it sit in a warm bath to get it to the 70 degree mark that I read about. Current pool temp is about 42 degrees here in sunny California.

Any ideas on what might be going on? Is my CYA test chemicals bad? Do I really not have any CYA? The chlorine loss makes me feel that way but the fact that there were pucks in the pool for the entire month that I was in contract on the house, I would think that there has to be some.

Tonight I put three pucks in the pool floater and will re-test again tomorrow to see what shows up.

Is there any way I can test the chemical to ensure it is working?

Your help is greatly appreciated.

P.S. I will be adding some washing soda to the pool tomorrow as well. Finally found a local place that has it.
 
Did you warm the water sample up to room temperature before doing the CYA test? Doing the CYA test with cold pool water can result in a false low reading. Allowing the CYA test mixture to mix for more than 30 seconds, say a minute or two, can help eliminate false low readings due to cold water, though getting the water warm is a better idea, or better yet do both.

It sounds like you have some conditioner, which is CYA, drop a crystal of that into a cup of water and stir occasionally for an hour or two and you will have a sample with an extremely high CYA level.

You didn't mention the FC level on the second test. That is the number that would allow us to make a rough guess of the CYA level based on how much FC you lost. If FC has been chronically low, it is common for CC to spike up when you first add chlorine. If CC doesn't go down again in a day you will need to shock the pool.
 
Do I really not have any CYA?
Click to expand...
That is very likely the case. The (probably) few pucks that were in the pool before you took over didn't add all that much. Add rainwater and possibly refill water to that and your CYA is so low to be undetectable.

I know I have an agenda here but the chances of the CYA reagent being "bad" is almost non-existent. We haven't had a report of that in five years, I think. The R-0013 reagent is perhaps the most stable reagent in the kit.

I suggest you simply ignore the CYA reading until you are ready to open the pool in the Spring. Your FC loss over the winter will be minimal and you shouldn't have algae issues at that water temp. If you want to get CYA in there regardless, target 30 ppm and dose the pool with that amount. Don't use the pucks to bring it up.....it'll be too slow over the winter.

For reassurance, you could test CYA at a pool store but I am pretty confidant saying your CYA is less than 20 ppm.

No hurry to lower the pH, either. 7.5 is fine.
 
It might be that they recently drained and refilled the pool. Then they did not properly balance the chemistry. Test the TA of your tap water, if it is 50, that may be a clue.
 
Update. Success!

Today I did the control test that Jason mentioned, and added some liquid conditioner to the 25ml pool water sample and tested with the cya test, and voila, cloudy water! So the testing chemicals are working, and I guess I just don't have any or an extremely low level of CYA.

Should I add the liquid conditioner that they left to get the CYA up some? I realize it is winter and super low water temp, but I'd just rather get everything balanced, and keep the pool in maintenance mode. I forgot to mention this, but the pool water appearance is clear.

Yesterday I added 2lb of baking soda, and test the pool again tonight.

My results were:
Ph 7.4 (hard to tell between 7.3 and 7.5)
CL .5
FC .5
CC .5 or less.
TA 50

Then per the pool calculator, I added approx 90 oz of 10% liquid chlorine and a guestimate of about 12oz of soda wash.

Just for fun, about a half hour later I did the quick chlorine/ph test (yellow/red) and ended up with at least 5 CL, and a PH closer to 7.5.

Thanks for all your help, and I'd love to hear anymore suggestions/recommendations.
 
Yes, you do want to get the water balanced correctly. it is important to maintaining the surface of the pool and the equipment. Low TA leads to low pH which is bad for skin, eyes, pool equipment and pool surfaces. Low or high CH can affect pool surfaces.

Please retest TA to see if you got the rise expected from the washing soda. You want to get up to 70 at a minimum.

I still would like to see what the tap water TA is. If it is low, then each time you add water or rain you are reducing the TA.
 
Tonights results:

PH 7.5
CL 5

FC 2
CC .5
TA 60


Made the following adjustments:
Added 7oz Washing Soda
Added about 40 oz of 10% liquid chlorine
Added half a gallon of the instant conditioner to the pool.

Did the CYA test after about 30 minutes, and somewhat passed the 20 PPM mark the water was quite cloudy in the vial, so I think I'm making progress.

Also, the tap water TA was 30.

Thanks again for all the feedback.
 
New Question.

The pool calc says to add soda ash/ washing soda for PH, and then the TA says to add 7lb baking soda. Should I just stick with one of those agents or add both?

Do they have different effects on the Ph?
 
Why are you adding washing soda? That mostly raise the pH. You want to use baking soda as that mostly raises the TA. The Pool calculator is giving you suggestions for each parameter and some are related. Make sure you understand what each chemical you add will actually do before you add it, ask for help if you do not understand.

You pH is fine, but the TA could go up a bit. Try not to adjust everything at once until you get a feel for what the chemicals do. Focus one one thing at a time.

Edit: have you seen the effects calculator at the bottom? Use that to start to see what each chemical will do.

Posted from my Droid with Tapatalk ... sorry if my response is short ;)
 

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Hi Jblizzle.

I added the washing soda based on the pool calc's recommendation. I may have underestimated the volume that I added, and now my PH is closer to 7.8. If I add baking soda at this point, wont this continue to raise the ph? I guess now I'm confused how to raise the TA while not impacting the ph. If I add muriatic acid to lower the ph, then add baking soda, which raises the ph, wont I be back to where i started??

I tested tonight, and these are my results after adding liquid bleach, conditioner, and the washing soda last night.

PH 7.8
CL 5

FC 3
CC .5
TA 70
CH 180
 
You're making good progress but if you don't mind, can we adjust your terminology a little? :)

Here are the parameters and abbreviations we like for them.
pH = pH (that's easy)
FC = Free Chlorine
CC = Combined Chlorine
TA = Total Alkalinity
CH = Calcium Hardness
CYA = Cyanuric Acid Level (Some pool stores call it Stabilizer or Conditioner)

I assume the CL listed in your posts is the chlorine reading from the K-1000 ph/Chlorine test. If it is, that's TC (Total Chlorine) which is FC + CC. That's a good go/no-go test for chlorine in the pool but you really don't need it if you're going to run the FAS-DPD test anyway. Once you get things under control and you learn the pool well you can use it as a daily check.
 
Baking soda has very little effect on pH. Use the effects calculator at the bottom of the poolcalculator to see that. Lower the pH and then raise the TA (although 70 is often not bad if you are using bleach or a SWG)

Posted from my Droid with Tapatalk ... sorry if my response is short ;)
 
Thanks for the info re: terminology. I will get the hang of this shortly. Promise!

Checked out the pool calc - effects calculator, and that would have been handy to have when I started lol! Will use that more in the future.

I'm under the impression that I have a concrete pool, so what should I be shooting for with CH?

Also, the stabilizer they left here is monosodium cyanurate (I believe), its the Leslies liquid instant pool conditioner. Is this okay to use or will the salt have any negative effects?
 
That CYA is fine. I think it is just the solid form dissolved in salt water. More expensive but the same thing and faster than the solid form.

Posted from my Droid with Tapatalk ... sorry if my response is short ;)
 
Just wanted to give an update and say THANK YOU! Your information on this website has been incredible! Spent our first weekend swimming in the pool and it looked amazing!
Bought some calcium Chloride to add to the pool and everything is looking good!

pH = 7.4
FC = 5
CC = 0
TA = 70
CH = 260
CYA = 40
Temp = 77



Thanks again.
 

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