CYA depletion rate in covered salt water hot tub????

[duganderson]

Curious if there is an estimate of the depletion rate of CYA in a covered hot tub with limited splash out? I run about 102 degrees and use a SWG with supplemental liquid chlorine deletions after use.

I've heard that salt water tubs can deplete CYA faster too but I don't know if that's true?

Thanks! Doug

 

[ajw22]

It is the heat, not the salt water, that causes CYA degradation.

High water temperatures will cause the chlorine to oxidize Cyanuric Acid. This tends to show in water temperatures of 90+ degrees. Every 10F increase in temperature results in roughly doubling the rate of degradation.

CYA - Further Reading

www.troublefreepool.com

 

[Mdragger88]

I find that I must use a little dichlor about once every week or so instead of liquid chlorine after a soak to replenish my cya. I run my tub around 104 degrees so my cya degradation may be a scootch higher than yours. If we have hot/sunny weather my tub has reached 107- 108 if I forget to turn it down in advance so this really increases the rate of degradation as well.

I made the mistake early on of not checking cya frequently enough & it fell to non existent levels all the while I was chlorinating the same as if I had 20-30ppm cya. I have a small tub so I often raise to slam level after a long soak so my swg is just the standby fc maintainer.
This frequent elevated fc/low cya condition resulted in a rust spot on the “stainless” ring of one of my jets. I assume the ring just isn’t that great of quality to begin with or perhaps there was an imperfection but nevertheless it served as a warning to pay more attention to my cya level to moderate the harshness of necessary fc levels on my equipment & surfaces.