High CYA and High FC

[Jenz]

Hi! I am new to the forum and just received my TF 100 which unfortunately confirmed what I feared.
18,500gallons
CYA off the charts on the TF100 (pool store said 151)
FC off the charts (pool store said 22.6)
ph 7.7
Total Alkanilinty 200

I had been using tablets and shocking every couple weeks before I learned better. Needless to say I have not been doing that for the last three weeks.
The pool water is clear and there is surprisingly little chlorine odor.

What should I do now about the CYA and chlorine levels? Is my pool safe to swim in?

Thanks so much.
Jen

 

[HermanTX]

Since you now have the TF100 kit, Let’s test the CYA using the dilution method.
Have you tested CYA with the new kit yet? It would require 1/2 pool sample and 1/2 R-0013 reagent in the mixing bottle. But since your CYA is over 100, use the dilution method below.

Pour pool sample in half way of mixing bottle, then pour tap water for the other half. Shake vigorously for 30 seconds.
Pour out half the solution to leave a diluted pool sample in the mixing bottle at the proper level for the CYA test.
Then add in the R-0013 reagent as per the instructions.
Shake that vigorously. Let sit, then shake one more time.
Pour into the CYA tube to measure CYA. Then take that number z2 to get your estimated CYA value.

Are you now using Liquid Chlorine to maintain FC?

 

[Donldson]

FC off the charts

The FAS-DPD test can accurately measure up to 50 ppm using the 10 ml test. Was it higher than that?

 

[Jenz]

Since you now have the TF100 kit, Let’s test the CYA using the dilution method.
Have you tested CYA with the new kit yet? It would require 1/2 pool sample and 1/2 R-0013 reagent in the mixing bottle. But since your CYA is over 100, use the dilution method below.

Pour pool sample in half way of mixing bottle, then pour tap water for the other half. Shake vigorously for 30 seconds.
Pour out half the solution to leave a diluted pool sample in the mixing bottle at the proper level for the CYA test.
Then add in the R-0013 reagent as per the instructions.
Shake that vigorously. Let sit, then shake one more time.
Pour into the CYA tube to measure CYA. Then take that number z2 to get your estimated CYA value.

Are you now using Liquid Chlorine to maintain FC?

Hi thanks for you reply! I did the tf100 cya test and the cya measure was higher than the tubes limit. I have not added any chlorine in a couple weeks because my FC level is 22.

 

[Jenz]

The FAS-DPD test can accurately measure up to 50 ppm using the 10 ml test. Was it higher than that?

Thanks for your reply!! I did not do that test. The color was just way more orange than anything in the regular chlorine test. My pool store recently tested it at 22

 

[Donldson]

You invested in one of the best test kits in the market, no better time to start taking advantage of it and kicking pool store testing to the curb than now.

 

[HermanTX]

Hi thanks for you reply! I did the tf100 cya test and the cya measure was higher than the tubes limit. I have not added any chlorine in a couple weeks because my FC level is 22.

Did you do the dilution test for CYA as outlined in the earlier post?

I would have assumed you are losing 2-3ppm per day so that is 7 days it should be down. Are you adding chlorine with pucks that still may be in the chlorinator.

 

[Jenz]

Did you do the dilution test for CYA as outlined in the earlier post?

I would have assumed you are losing 2-3ppm per day so that is 7 days it should be down. Are you adding chlorine with pucks that still may be in the chlorinator.

I did the test just like that. I closed the valve on my chlorine puck dispenser about two weeks ago. Do I need to drain the pool? Or will the cya dissipate with time? Would it be better to leave the cover open? Thank you!!

 

[dereksanders]

There’s not enough time left in the season for that much CYA to dissipate from natural cause.

 

[Bperry]

Thanks for your reply!! I did not do that test. The color was just way more orange than anything in the regular chlorine test. My pool store recently tested it at 22

Use the FAS-DPD, not the yellow OTO test.

 

[Jenz]

There’s not enough time left in the season for that much CYA to dissipate from natural cause.

so are you suggesting I drain the pool?

 

[dereksanders]

I merely stated there’s not much season left to naturally lower your CYA. I haven’t seen a CYA value listed from your own test. If I missed it I apologize. With very high CYA your options to do anything in the way of everyday chlorinating and SLAM chlorinating are challenging.

Closing your pool will also be difficult to avoid a mess in the spring.

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

 

[Gary Davis]

I feel for you with CYA levels that high. You can't do all that much to get rid of it.
Sure, reverse osmosis or those brand new chelating agents "might" work but they'll be expensive (and have drawbacks).
You don't have much choice the way I see it other than to dilute.

 

[HermanTX]

I did the test just like that. I closed the valve on my chlorine puck dispenser about two weeks ago. Do I need to drain the pool? Or will the cya dissipate with time? Would it be better to leave the cover open? Thank you!!

If your diluted test yielded, for example 150 ppm for CYA then you need to drain 2/3 of the pool to get to 50ppm. If your CYA was 200ppm then you need to drain 75% of the pool to get to 50ppm. Draining is proportional to the desired CYA level.
For use of liquid Chlorine then a CYA of 50 should be your target.

Draining is the only true way to reduce CYA. Do not buy any additives that say they reduce CYA because they do not work. CYA may degrade a little over time but that is not helpful to correct your issue.

You mentioned the pool is 18,500 gals but is it a plaster pool, fiberglass or vinyl?
If plaster you want to limit plaster to the exposure to sun when it is partially drained. If vinyl, you want to always keep some water in the bottom 12-18 inches to keep the vinyl in place.
Please read Draining - Further Reading

 

[Jenz]

I merely stated there’s not much season left to naturally lower your CYA. I haven’t seen a CYA value listed from your own test. If I missed it I apologize. With very high CYA your options to do anything in the way of everyday chlorinating and SLAM chlorinating are challenging.

Closing your pool will also be difficult to avoid a mess in the spring.

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

Thanks for your help. The pool draining takes forever for me because I need a 300ft hose to get it to a safe place to drain. But it sounds like that is my best bet.

 

[Gary Davis]

Thanks for your help. The pool draining takes forever for me because I need a 300ft hose to get it to a safe place to drain. But it sounds like that is my best bet.

That's a long distance for sure. If you need a good pump to drain the pool, this pump drained my pool overnight (but I dumped the water on the lawn so that the water goes back to my well, eventually).