Temperature and CyA degradation in a hot tub

[AUSpool]

Do higher temperatures (101-104oF) degrade CyA in a hot tub quicker then what we generally see in outdoor pools? Has anyone actually kept any data?

I’ve swapped out my pool for a hot tub for the next few weeks, it’s managed, serviced 3 times a week. Very basic setup, trichlor tabs in a floater, I guess thats quite common. The service guy said it will have a water change after the Xmas new year period. I had been thinking about the effect of temperature recently and wondered if the rate of increase in CyA due to the trichlor would be slower in a hot tub due to the higher temperature.

 

[JoyfulNoise]

All reaction rates will increase with temperature and the oxidation of CYA by chlorine is no different. Richard has a little bit of information at the bottom of this post in his thread on the topic -

Degradation of Cyanuric Acid (CYA)

This thread explores some of the ways that Cyanuric Acid (CYA) can degrade since many users report seeing CYA drop under various conditions. CYA Degradation by Bacteria Some pool users find that their CYA levels drop over the winter when their pool is let go (i.e. no chlorine added). Many of...

www.troublefreepool.com

 

[AUSpool]

Thanks for that. So a little bit but not much more then a pool 90oF.

So I can see that it is possible for CYA to degrade slowly over time in pools that are at higher temperature or at higher FC/CYA ratios such as extensive periods of shocking. The inconsistency is in how much degradation is occurring from sunlight vs. oxidation from chlorine.

One thing I have noticed about these hot tubs is that the veiw is much better then my back yard pool, but for some reason it makes my legs hurt.

 

[Mdragger88]

Just caught your thread,
In my experience the cya certainly degrades faster at the higher temps.
I keep my tub at 104 degrees and I really have to keep tabs on my cya level & replenish it by about 5ppm every week or so or it’s undetectable.
Btw Trichlor tabs aren’t recommended for a covered tub - the higher temps make them erode quickly which can lead to a high fc & acidic condition. While the hotter water leads to faster cya degradation I doubt it keeps pace with amount added by the tabs. Just 1oz of dissolved Trichlor adds nearly 10ppm of cya to a 450 gallon tub. I imagine 1oz is dissolved quite quickly.

 

[AUSpool]

Just caught your thread,
In my experience the cya certainly degrades faster at the higher temps.
I keep my tub at 104 degrees and I really have to keep tabs on my cya level & replenish it by about 5ppm every week or so or it’s undetectable.
Btw Trichlor tabs aren’t recommended for a covered tub - the higher temps make them erode quickly which can lead to a high fc & acidic condition. While the hotter water leads to faster cya degradation I doubt it keeps pace with amount added by the tabs. Just 1oz of dissolved Trichlor adds nearly 10ppm of cya to a 450 gallon tub. I imagine 1oz is dissolved quite quickly.

We don’t have any say over how this tub is managed as its a holiday rental. There’s a guy that comes every two days. It does have a strong chloramine smell and its only being used by two people for about 30 minutes every second day. I’ve had to stop using it as its been making me itch like a dog with fleas. Zertec is my friend. I’ve never had any reactions to our pool at home. The view is still pretty special though.

 

[Mdragger88]

We don’t have any say over how this tub is managed as its a holiday rental. There’s a guy that comes every two days. It does have a strong chloramine smell and its only being used by two people for about 30 minutes every second day. I’ve had to stop using it as its been making me itch like a dog with fleas. Zertec is my friend. I’ve never had any reactions to our pool at home. The view is still pretty special though.

View attachment 549221

I gathered it wasn’t yours - that was mostly a disclaimer for other readers.
I bet the cya is quite elevated if the water is not new. Hopefully the itchiness is from the ph not lack of proper sanitation. I can’t believe you didn’t bring your kit on vacay lol

 

[AUSpool]

I gathered it wasn’t yours - that was mostly a disclaimer for other readers.
I bet the cya is quite elevated if the water is not new. Hopefully the itchiness is from the ph not lack of proper sanitation. I can’t believe you didn’t bring your kit on vacay lol

I did think of packing a test kit but given the space and weight constraints the only choice was a pack guess strips and that was not happening.

We’ve had a bit of a cold snap. Cant go out to the tub. We’re currently sitting on -32C/23F. I wonder how long it would take to turn it into an ice block if we had a power failure.

 

[JamesW]

We’re currently sitting on -32C/23F.

(-32°C × 9/5) + 32 = -25.6°F

y = (x − 32) × 5/9, y from -50 to 100 - Wolfram|Alpha

Wolfram|Alpha brings expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels.

www.wolframalpha.com

 

[JamesW]

We’re currently sitting on -32C/23F.

Seems a little chilly for Brisbane?

 

[AUSpool]

Seems a little chilly for Brisbane?

Sorry I didn’t this. Escaping the summer heat and storms for a winter wonderland.

Thanks for the correction, -25.6F, I shouldn’t rely on google. Although it could have just been me. It was still cold. And just a few days before they had to close the ice rink because it was too warm.