CYA/Chlorine Loss

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poolflyer

Member
Aug 1, 2023
7
Central Florida
Pool Size
12500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-30 Plus
I wrote the long version of this post and decided it was too long :ROFLMAO:

So I'll make it short and sweet: my CYA was ~50 and trying to get it to 80.
Specs: 12,500 gallon pool, I am recirculating about 24,000 gallons a day on a VSP with RJ30+ SWG. Using Taylor K2006 test kit.

  1. How long does liquid CYA take to show up in a CYA test?
  2. Does CYA ever zap chlorine out? Twice I've had this happen adding liquid CYA this week. Took my chlorine from ~6 to 2, then another time from 6 to 0.2. (added 1/3 a gallon the first time, then the rest a few days later). Is this normal?
  3. Follow up to question above. Twice this week I've added CYA and not only did it zap my chlorine, but also showed a small amount of combined chlorine (about .2). Is this normal? Just seems to be within 24 hours after I add liquid CYA to the pool. I've never seen anything but 0 so far in this pool. A day later, it disappears, once I get my FC back to ~6. Is this normal?
  4. Completely unrelated- before trying to get the CYA up, it's been incredibly problem free. All my levels are nearly perfect. I've had the SWG running on 25% for 4 hours, generating about 0.7 PPM FC per day for my pool. This seems to be the perfect amount, keeping FC about 6. It seems to lose just a little less than that per day, losing about .4-.5 PPM per day. Pool is at ~69F. Some days have been sunny and warm @75F, some days have been Florida cold ~60F (and rainy). We have had a ton of pollen the last few weeks. Is this a normal amount of FC consumption?
Thank you! This forum is amazing and so happy with my results so far.
 
1. Immediately. 10-30 minutes to circulate
2. No. Possibly some insignificant loss but still, No
3. Any CC test result of .5 or less is ZERO
4. Is there a question?

TREAT CC test as ZERO if it is .5 ppm or less........Always
 
Two thoughts :

1) switch to 10ml pool samples for FC / CC. There's is simply no need for .2 resolution. A 2.X sucks across all CYA levels. I don't even care what the X is. It could be a 2.9 and I stand by my original comment. On the other hand, a 8.X is equally awesome for most CYA levels.

Anywho, at 10ml with each drop being .5, you save 2.5X the supplies and still know the important part.

2). Wanted to make sure you understand that daily FC loss will spike soon in FL. The days are getting longer and the sun is slowly rising in the sky. It will increase until the mid season and then slowly decrease for the back half of the season. We are at the blue X right now with little to no daily loss.

Screenshot_20240219_144105_Chrome.jpg


There can be a whoospie week in there that goes sideways high or low, but for the most part it follows the general plan.

The 1st halt of the season you underproduce when you miss an adjustment time and may be gifted a swamp so it's pay attention time. Catching the FC getting lower is how you know it's time to raise FC production either by % or runtime.


In the back half you overproduce when you miss an adjustment and there's no swamp gifted when you catch the FC in the teens. You'll lol and turn the SWG down/off until the FC gets back into range.

Now. Let's get to the daily target that's currently 6. That's fine and dandy now when you are losing less than 1 FC per day. But when you are losing 4 or even 5 daily in the peak season, it's cutting it way too close. One hiccup and the SWG doesn't add today's dose and you're below min. Adjust your target up as the daily loss increases. Many of us sit just above target level and fall back into it when things swing a little.

swcg_chart.jpg
 
Last edited:
poolflyer said:
How long does liquid CYA take to show up in a CYA test?
Click to expand...
I use the sock method hanging in my pool in front of the return to add granular stabilizer to my pool.
I find it may take 36-48 hours to accurately show the increase in CYA value. Liquid stabilizer may be quicker to mix.
I run my pump 24/7 so continuous circulation
 
Last edited:
poolflyer said:
Does CYA ever zap chlorine out? Twice I've had this happen adding liquid CYA this week. Took my chlorine from ~6 to 2, then another time from 6 to 0.2. (added 1/3 a gallon the first time, then the rest a few days later). Is this normal?
Click to expand...

Short answer: No, this is not normal. How long before and after did you test FC?

I have never used liquid CYA, so can't speak from experience. I can only imagine that, if there is such an effect, it is due to some impurities in the product.

I'd suggest to switch to dry CYA anyway. The liquid stuff can be tricky to dose, as the CYA tends to form a sludge at the bottom of the bottle. When not using the complete bottle, you tend to add diluted CYA, and then the next time there is the risk to overdose. And to get everything out, the bottle needs to get rinsed a couple of times.


poolflyer said:
Completely unrelated- before trying to get the CYA up, it's been incredibly problem free. All my levels are nearly perfect. I've had the SWG running on 25% for 4 hours, generating about 0.7 PPM FC per day for my pool. This seems to be the perfect amount, keeping FC about 6. It seems to lose just a little less than that per day, losing about .4-.5 PPM per day. Pool is at ~69F. Some days have been sunny and warm @75F, some days have been Florida cold ~60F (and rainy). We have had a ton of pollen the last few weeks. Is this a normal amount of FC consumption?
Click to expand...

Seems to be within normal range. Over winter, my SWG produces about 0.25ppm per day to keep FC constant at about 10. Pool is completely shaded in winter. In summer, this ramps up to 2-3ppm per day.

Pollen doesn't consume FC.
 
Thank you all for the information!

I now understand why I need to be aiming my FC for higher to have that big buffer— this week proved that! Albeit we did have a ton of rain- several inches.

All the times I did the testing when the chlorine was lost after adding the liquid stabilizer, the FC was measured less than 24 hours apart. I think it’s best I switch to dry stabilizer in the future. My first jug from Leslie’s had a ton of sludge and the Natural Chemistry from Amazon (same exact brand as Leslie’s) had almost no sludge. One of my biggest concerns is why it seems like this recent bottle didn’t add but about 1/3 what it was supposed to, and how it seemed to lose CYA about ~15PPM in just about 3 weeks. I had already ordered another bottle before I posted this, so I’ll add this one and see how the levels are and test the CYA more often!

Thanks for all the input!
 
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The goods clump on the bottom and partial jugs are almost impossible to dose correctly. Your only chance is to use the full jug and rinse it real well so it's empty.

IIRC it was 4X the price for me here for strike 2.
 
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