CYA loss

[mikemo]

I've done a bunch of searching but can't find an answer to this. Where does the CYA go???
I test my own chlorine (fas/dpd) but rely on the pool store to test cya. When I notice my chlorine levels dropping I take a sample to the pool store and they tell me my cya is low. I assumed that cya was like salt, that overflow from rain and filter flushing is the only way to lose it. Is that true? Should my cya track my salt levels?

In the last month, my cya has dropped from 80 to 25, but my salt has been stable at around 3000. Does the sun normally eat up some of the cya?

As an aside, this forum and the info I learned have been a lifesaver. I no longer struggle with my pool. I was close to getting a dump truck full of dirt and filling it in Now, it is clear and beautiful all the time.

11k gallon pebble tec pool
goldline swg
Hayward DE filter

Thanks,
Mike M.

 

[duraleigh]

Hi, Mike,

Your comparison of salt and CYA is accurate. They should both be relatively stable in your pool. Splashout gets some and rainwater dilutes it.

Like everything, there are some caveats but not applicable to you.

Biggest likely problem?............Pool store testing.

Get your own CYA test and you will KNOW what your CYA levels are rather than depending on the pool store results which tend to vary probably the widest on CYA.

 

[BadOleRoss]

IMO, the pool store loves you to have more CYA in your pool! The higher your CYA, the more chlorine you will by. My pool store told me my CYA was 30 and had me add more to the pool. When I found TFPs and got my own test kit, my CYA was around 200. The pool store printout I received says an acceptable CYA range is 30-300! Can you imagine the chlorine you would need with a CYA of 300? Might was well back up a truck and dump pit in!

 

[chem geek]

Can you imagine the chlorine you would need with a CYA of 300? Might was well back up a truck and dump pit in!

Or imagine the amount of phosphate remover or algaecides that they would sell you to prevent algae growth!

 

[rcy]

Yeah, get your own test kit. This past week, my pool store showed 30, my K2006 showed 55.

A few weeks ago, same pool store showed 15, after I had put two kilograms of CYA in the pool. K2006 showed 60, another pool store showed 55. I told the first pool store manager they needed to calibrate their Waterlink Express (which is normally 'somewhat' reliable). Next time I went in to the pool store, they were still using the Waterlink, but at least they were testing the CYA manually. Still, the recent reading of 30 vs my 55 indicates something is still not right. I can only imagine the number of pool owners using that store that are now overstabilized.