CYA Test Frequency

[Bicster]

Guys,

Quick CYA question - my understanding is that CYA doesn't go away and the only way to reduce it is to replace water in your pool. Based on that logic, I would assume the only thing that causes CYA to naturally drop over time is through usage of the pool (spillage/evaporation etc...).

So, am I right in thinking that once you've got your CYA level to where is needs to be, that's pretty much it? You check maybe every week (or once a month?) but it's not something you would typically check as regularly as PH and FC.

Is that right?

Bic

PS Also, am I right in thinking 30-50 would be a the target CYA range for my pool?

 

[mknauss]

30-50 ppm CYA is a good target in your climate.

CYA does degrade over time. More so in high water temperatures and elevated FC. In my pool, in the summer, with pool water temperature near 90F, I lose about 15 ppm CYA per month. In your climate, with lower water temperatures, you might see 5 ppm per month in the summer.

Testing CYA monthly is sufficient.

 

[Bicster]

I'm moving away from stabilized chlorine to bleach, so will need to manage my CYA - so this is all great information, THANK YOU!

 

[riley00dog]

Mine started at 80 (pool guy tested it at 90) in mid May when my new pool was filled. Now at mid August it’s down to 60 so I’ve lost about 20ppm over 3 months. Pool is heated to 30*C. I definitely don’t test as often as FC or ph. The test kits don’t allow for testing that frequently. You would be replacing reagents constantly. I test mine every 2-4 weeks. I was a little obsessive about it in the beginning but now know that it won’t change all that quickly without water exchange or other deliberate actions.

 

[riley00dog]

Btw, I have a swcg hence my higher target level of cya.

 

[phonedave]

Guys,

Quick CYA question - my understanding is that CYA doesn't go away and the only way to reduce it is to replace water in your pool. Based on that logic, I would assume the only thing that causes CYA to naturally drop over time is through usage of the pool (spillage/evaporation etc...).

So, am I right in thinking that once you've got your CYA level to where is needs to be, that's pretty much it? You check maybe every week (or once a month?) but it's not something you would typically check as regularly as PH and FC.

Is that right?

Bic

PS Also, am I right in thinking 30-50 would be a the target CYA range for my pool?

Just FYI, evaporation does not change CYA. Aside from the slow natural degradation of CYA, it will only go down if you remove the liquid water it is dissolved in - splash out, overflow from rain, vacuuming to waste, backflushing, etc.

It pretty much works like salt, except salt does not degrade.

 

[Oly]

Mine started at 80 (pool guy tested it at 90) in mid May when my new pool was filled. Now at mid August it’s down to 60 so I’ve lost about 20ppm over 3 months. Pool is heated to 30*C. I definitely don’t test as often as FC or ph. The test kits don’t allow for testing that frequently. You would be replacing reagents constantly. I test mine every 2-4 weeks. I was a little obsessive about it in the beginning but now know that it won’t change all that quickly without water exchange or other deliberate actions.

Here you can get a 16oz bottle of CYA reagent for under $12.

 

[Bicster]

Just FYI, evaporation does not change CYA. Aside from the slow natural degradation of CYA, it will only go down if you remove the liquid water it is dissolved in - splash out, overflow from rain, vacuuming to waste, backflushing, etc.

It pretty much works like salt, except salt does not degrade.

So if 10% of the water in my pool evaporated, are you saying the CYA reading would go up as there's a higher volume of CYA relative to the volume of water?

 

[Oly]

Yes, assuming you don't top off the pool with tap water. Realistically I doubt you would be able to detect the difference given the precision of the turbidity test for CYA.

 

[Rollercoastr]

So if 10% of the water in my pool evaporated, are you saying the CYA reading would go up as there's a higher volume of CYA relative to the volume of water?

Yes, but only if you didn't replace that water. That's a big "if", because 10% drop would likely be below your skimmer.

 

[ashtonfitzgerald]

I keep my cya at 40 and that works well for our climate. I had to bump it this year due to the substantial rains we've had this summer--lots of back washing to lower the water level. Used some granular cya, then pucks while we were out of town. Sitting pretty at 40. I usually test it monthly just to be safe.