Can't Keep CYA UP

[manfacro]

Hi All,

I've been having a fun time with CYA in my pool, it seems to go away all to quickly. Scale of events,

Aug 2018: Drained half pool to go from 140 to 70
Oct 2018: Dropped to 30
Feb 2019: Added to get up to 70. tested at 70
Apr 2019: (Today) Tested at 50, adding some to get to 80

Since October I've added enough CYA to get the pool to 100 (Per Pool Math), but it seems like it's just vanishing. There has been some water loss do to a leak this spring, but minimal amount of water was exchanged compared to the main pool volume. But even last year, dropping so drastically on its own, I know heat can kill it and we are in the Florida sun here, but for something that shouldn't go anywhere, it sure doesn't like staying in my pool. Any ideas? I've read on here that folks that close their pool and reopen it in the spring will normally test with no CYA. Does it age out, or have a lifespan that I'm running into having the pool open year round?


Thanks for any pointers!

 

[cfherrman]

It's often give a loss of 5 ppm per month, people that have heated spas lose more.

I think your 2019 cya difference might be testing error

 

[djdonte]

You will lose some over time with rain dilution and splashing but it should be very minimal. Honestly I think the CYA test is very subjective and takes a while to get the hang of. Sometimes its tough to tell when you really can't see the black dot anymore. Do you stop when the dot is super fuzzy, or when all you can see is cloudy water? I wish there was a better way.

 

[manfacro]

You will lose some over time with rain dilution and splashing but it should be very minimal. Honestly I think the CYA test is very subjective and takes a while to get the hang of. Sometimes its tough to tell when you really can't see the black dot anymore. Do you stop when the dot is super fuzzy, or when all you can see is cloudy water? I wish there was a better way.

I am not a huge fan of the Taylor CYA test, after I finished those reagents I purchased the Blue Devil test, it has a bigger tube with a dot on a stick so it can be checked many times and not have to transfer stuff back to a bottle to double check. I go till dot is completely gone, then round up to nearest 10.

It's often give a loss of 5 ppm per month, people that have heated spas lose more.

I think your 2019 cya difference might be testing error

It’s possibly and error, I’ll tend to test a couple times if I think the number is off. I try to do it in the same light, looking for the same thing so any difference is just the water. I didn’t realize a loss of 5ppm monthly is normal, thanks for the info. As of today my pool is pretty warm (87), so if heat really does kill CYA, I could see it happening.

 

[mknauss]

Higher water temperatures do lead to faster CYA degradation.

 

[djdonte]

I am not a huge fan of the Taylor CYA test, after I finished those reagents I purchased the Blue Devil test, it has a bigger tube with a dot on a stick so it can be checked many times and not have to transfer stuff back to a bottle to double check. I go till dot is completely gone, then round up to nearest 10.


It’s possibly and error, I’ll tend to test a couple times if I think the number is off. I try to do it in the same light, looking for the same thing so any difference is just the water. I didn’t realize a loss of 5ppm monthly is normal, thanks for the info. As of today my pool is pretty warm (87), so if heat really does kill CYA, I could see it happening.

Hmm that test looks interesting. Can i use my TF-100 reagent refill with it? If you are supposed to go all the way until not seeing the black dot at all then I have like 30-35 CYA and that would explain why I'm losing a ton of FC during the day and zero at night.

 

[cfherrman]

Yeah blue devil and Taylor are interchangeable. The important thing is to do the test the same way, in the same light, every time. Fill it to the line, glance in the tube, if you don't see the dot in a quarter second your done. Pour back in the mixing tube and try again till you're happy.

 

[aussieta]

how are you adding your cya, not into skimmer i hope
back at the end of last year you didnt add any magic potions to try and lower cya did you
are you keeping your fc levels correct
are you having to add more salt as well

 

[manfacro]

how are you adding your cya, not into skimmer i hope
back at the end of last year you didnt add any magic potions to try and lower cya did you
are you keeping your fc levels correct
are you having to add more salt as well

how are you adding your cya, not into skimmer i hope
back at the end of last year you didnt add any magic potions to try and lower cya did you
are you keeping your fc levels correct
are you having to add more salt as well

No magic potions, SWG is new so still on the initial salt levels... that’s a great idea, I didn’t think that the concentrations should both drop if it’s a water loss, or splash out situation. FC has been pretty consistent sense SWG.

I normally add the CYA to a bucket of water to dissolve, it usually takes a day or so to break down but then I just broadcast that in the pool, sometimes I do that in the skimmer... but when it’s dissolved it’s passing through all that quickly.