CYA Low, FC Normal..What to do?

mayberry32

Silver Supporter
Jun 24, 2019
132
Watkinsville, GA
So, after our pool was finished a few weeks ago, I've used my TF-100 kit almost daily, just trying to learn the relationship with all the chemistry. My recommended CYA with a SWCG is 60-80, according to the charts in my test kit, and also here in Pool School. Mine CYA is consistently 50 in all the tests I'm running. My FC is hovering between 4.5-5.5 and my CC is 0 (occasionally .5, but no higher). Everything else is right on point. My water is clear and feels great. Water temp is 86 in the afternoons and 83 in the mornings right now, if temp matters, and affects the chemistry. I know I add stabilizer/conditioner to raise the CYA, but then the recommended FC goes up, too. Should I leave it alone, and allow my CYA to stay at 50, or do I need to raise it somewhere between 60-80, even if I'm not seeing an immediate problem?
 
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Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,201
Bedford, TX
32,

You can run your CYA at whatever level you want... The whole point about have a CYA of 60 - 80 with a SWCG is so that you do not have to run the cell as hard to generate the chlorine your need.. This time of year, that is not much of a problem compared to the middle of the summer.

Thanks,

Jim R.
 

mayberry32

Silver Supporter
Jun 24, 2019
132
Watkinsville, GA
It's middle of summer here. In GA, we've had a big heat wave, with highs around 96-98 every day, and no rain. I'm running my SWCG at 60%, because I upsized it during the build, per recommendations here. So, I am not running my SWCG hard at all, and my levels are where they are.

So, would you recommend not adding the conditioner and leaving things where they are? I don't want to screw anything up by adding it, if it's not needed.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
9,737
Northern NJ
Sounds like you are doing fine. I would not tinker with things.

What is your % setting on the IC60 and how long do you run your pump for?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
9,737
Northern NJ
Heat is not the reason for CYA level. CYA protects the chlorine from the suns UV rays. Intensity of UV depends on sun angle. Sun angle is at its peak in late June. So UV intensity has been declining as we get into fall. CYA 50 is likely fine for you in the coming months. Monitor it and increase it next Spring.

Hot pool water will degrade CYA. If it drops below 50 then I would increase it to 60-70.
 

mayberry32

Silver Supporter
Jun 24, 2019
132
Watkinsville, GA
Also forgot to mention that my TA is running 100-120, so that is also a little higher than recommended levels. Should I do anything to get that down, or is it okay running 100-120?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
9,737
Northern NJ
Also forgot to mention that my TA is running 100-120, so that is also a little higher than recommended levels. Should I do anything to get that down, or is it okay running 100-120?
Please post a complete set of test results. You need to look at the overall water balance not just pick on one chemical. Best way is to share Test Logs using PoolMath. Or post:

FC
CC
pH
TA
CH
CYA
 

mayberry32

Silver Supporter
Jun 24, 2019
132
Watkinsville, GA
Thanks. It's been 2 weeks and it's staying the same. So, over another few weeks or month, I should see TA reduce on its own?

My pH naturally wants to stay in the 7.8 range. The pool builder said that saltwater pools want to run a little on the high side of pH and I'd have to dump acid in it every week to keep it below 7.6. So far, he's been correct. Even when I added acid last week, it went down to 7.2 that night and was back to 7.8 the following afternoon.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,201
Bedford, TX
32,

Your pool builder is not giving you very good advice... You should just let your pH sit at 7.8 and only add acid when the pH hits 8.0.. Then, only add enough acid to reduce the pH to 7.7 or so... As long as your TA is above 50, you are just fine.

Thanks,

Jim R.
 

mayberry32

Silver Supporter
Jun 24, 2019
132
Watkinsville, GA
Sorry, I said that incorrectly. He didn't say I SHOULD add acid every week. He said that's what I'd have to do to keep my pH low. He said to let it sit around 7.6-7.8 naturally and it would be fine...same as you are saying.
 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
9,737
Northern NJ
Your TA is fine at the level it is. If it comes down due to pH adjustments that is ok. You don't need to do anything specifically for TA. Just manage pH.
 

mayberry32

Silver Supporter
Jun 24, 2019
132
Watkinsville, GA
Yup.

You are really looking for something to do with your pool? Go brush it.
Lol....Already done. Huge thunderstorm rolled through last night and completely covered the pool in leaves. I cleaned it while watching football earlier. Now, I'm bored and looking for something to do.

Seriously, sorry for all the repetitive questions. I'm just working to understand the chemistry and thought everything needed to be within the recommended ranges. Pool looks great, water is clear. This is just my first pool and I don't want to slip up and let it get away from me.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
9,737
Northern NJ
Seriously, sorry for all the repetitive questions. I'm just working to understand the chemistry and thought everything needed to be within the recommended ranges. Pool looks great, water is clear. This is just my first pool and I don't want to slip up and let it get away from me.
No problem with the questions.

The ranges are there to simplify the chemistry and have been designed to keep most pools out of trouble.

If you want to learn more about the chemistry then learn about the CYA Chlorine Relationship - Further Reading and the pH/TA relationship. I have not seen a simple writeup ont he pH/TA relationship and plan to write one soon.

CH and TA affect your CSI. You don't have to worry much about CSI with your vinyl pool. But you do need to keep an eye on your CSI to prevent scaling of your SWG.

So you cannot just focus on an individual number when changing one changes other chemistry.

TA only needs to be adjusted if the pH is having problems staying stable, high or low. If the pH is stable then any value of TA is fine. Except that TA also contributes to CSI. And if CSI is out of range then TA may be the best one to be adjusted.

That is the bigger picture of water chemistry that some of us look at when you ask if a single value is good. And why we ask for a complete set of test values.
 
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beautifulpool

Well-known member
Jun 2, 2019
102
North TX
32,

You can run your CYA at whatever level you want... The whole point about have a CYA of 60 - 80 with a SWCG is so that you do not have to run the cell as hard to generate the chlorine your need.. This time of year, that is not much of a problem compared to the middle of the summer.

Thanks,

Jim R.
My favorite chlorine of all time (once upon a time) was Di-chlor. The water didn’t cloud and was instantly sparkly. But continued use of di/chlor caused a colossal Pool nightmare! And more than once!
How I learned CYA doesn’t degrade but continues accumulating, was having a front row seat at my backyard pool! As my cya levels rose, my pool’s chlorine’s ability to Sanitize, slowed and eventually QUIT!! Mentally, i knew I had to quit using stabilized chlorine. But, in full disclosure ..., it took another Pool drain and 3 more years to completely wean off CYA pool products looking back, i now think cya users are more addicted than they realize and have bought in deeper to the Pool industries CYA culture than we know .I needed CYA users anonymous..... cause I kept running back when time ran short in a day ....
 
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