FC Up & Down - Do I need to SLAM

nrobfd_pl

Well-known member
Feb 8, 2023
117
Missouri
Pool Size
25611
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
My water has been crystal clear. It's maybe a little cloudier today. CC has been under .5 when tested. The past couple days my FC is bouncing up and down. During some of this time I used the Superchlorinate feature on my IC60 (but only for a few hours at a time). My logs are in my signature, some of the testing is with my K-2006C, some is via Sutro. I've been struggling to dial in my IC60 and am not sure if this is just getting used to it trying to find the right number or if something else is going on. Also may be relevant, the pool is covered almost all the time unless we're swimming (family of 7) and the past few days it's been partially open as I've been aerating to raise the pH.
 
If you have a question in there, I have missed it.

We only care about the results you get from the Taylor K-2006C.
My question is: is it normal for fc to be up and down like this or is it a sign I need to slam even though my CC is low?

Also, FWIW, every time thus far when I’ve compared the Sutro’s results to the K-2006C, they’ve been right on.
 
My question is: is it normal for fc to be up and down like this or is it a sign I need to slam even though my CC is low?

Also, FWIW, every time thus far when I’ve compared the Sutro’s results to the K-2006C, they’ve been right on.
Which of your logs are from the K2006C? Can’t really compare results from the sutro. It’s hard to tell but the FC levels look like they got below minimum several times so you could have something brewing. Do an overnight chlorine loss test and see if something is consuming chlorine excessively.
 
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Also, FWIW
No sarcasm meant, but it's worth bupkis to us. We've seen them off too many times to dose from them. You can prove yours ok, and act accordingly, by all means. But we'll always want the tried and true results. :)
My question is: is it normal for fc to be up and down like this
It depends. A SWG can maintain FC well if it's running all day as the UV depletes the FC. If you run overnight only, or only for a short time during the day, it will fluctuate more like a LC pool.

Either way, aiming for 5FC is a fools errand. It's totally possible, but it's also totally possible to have 3 power outages this season, a couple really high UV days out of character, or a couple of low salt alarms from big storms before they mix well. Any given day it will probably be fine, but there will be a handful if days it's off, one way or the other. We updated the SWG chart for this exact reason to allow a range to account for all the variables. Always aim high, and you'll be covered when a high loss or no production event happens.

swcg_chart.jpg

Overnight Chlorine Loss Test as said above. If you prove there's no swamp on the horizon, we have time to tweak your CYA (50 is low for Mossouri) and dial in more SWG runtime.
 
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No sarcasm meant, but it's worth bupkis to us. We've seen them off too many times to dose from them. You can prove yours ok, and act accordingly, by all means. But we'll always want the tried and true results. :)
I get it. For me, it's not about relying on it, it's more about keeping an eye on general trends (especially pH). I'll still be testing regularly with the K2006C.

It depends. A SWG can maintain FC well if it's running all day as the UV depletes the FC. If you run overnight only, or only for a short time during the day, it will fluctuate more like a LC pool.
Mine should be running 24/7, and the UV exposure should be much less than a typical pool since it's covered except when we're in it (and most of yesterday since I was trying to raise the pH back via aeration).

Either way, aiming for 5FC is a fools errand. It's totally possible, but it's also totally possible to have 3 power outages this season, a couple really high UV days out of character, or a couple of low salt alarms from big storms before they mix well. Any given day it will probably be fine, but there will be a handful if days it's off, one way or the other. We updated the SWG chart for this exact reason to allow a range to account for all the variables. Always aim high, and you'll be covered when a high loss or no production event happens.

View attachment 506112

Overnight Chlorine Loss Test as said above. If you prove there's no swamp on the horizon, we have time to tweak your CYA (50 is low for Mossouri) and dial in more SWG runtime.
CYA might be 60, test was borderline 50/60. It was definitely 60 before I topped off the water earlier this week.
 
Mine should be running 24/7, and the UV exposure should be much less than a typical pool since it's covered except when we're in it (and most of yesterday since I was trying to raise the pH back via aeration).
Ok. HUGE part of the equation here. You should easily maintain FC.
CYA might be 60, test was borderline 50/60. It was definitely 60 before I topped off the water earlier this week.
I redact my above comment because the pool is covered and UV won't typically be a concern. 50/60 should be fine and if you have any long swim days, keep tabs on it.

OCLT to see if it's algae or the cell acting up.
 
Ok. HUGE part of the equation here. You should easily maintain FC.

I redact my above comment because the pool is covered and UV won't typically be a concern. 50/60 should be fine and if you have any long swim days, keep tabs on it.

OCLT to see if it's algae or the cell acting up.
Also, I deleted all the non-K2006 test results from the logs (and accidentally one K2006 test from yesterday :().
 
We have approximately the same size pool and equipment including the autocover. What is your IC60 percentage set at? I run FC on the upper end of the target range for my CYA70 for my environment. Target being 5 - 10, I am always around FC10 most days. If I don't open my autocover earlier enough in the day, i.e. around noon, FC will rise above 10.

When my FC starts to drop more than I like, i.e. from FC 10 one day to FC 8 or so, I check my CYA. It may have dropped from 70 to 60 then I will bump it back up to 70 to stabilize my FC losses. My IC60 is currently set to 27%, the pump runs 24/7 which adds 2.5 FC a day.
(M)
 
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Also, I deleted all the non-K2006 test results from the logs (and accidentally one K2006 test from yesterday :().
FC levels look more normal now. Can expect to lose a few ppm each day and need to adjust the SWCG to account for that and changing weather.
 
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We have approximately the same size pool and equipment including the autocover. What is your IC60 percentage set at? I run FC on the upper end of the target range for my CYA70 for my environment. Target being 5 - 10, I am always around FC10 most days. If I don't open my autocover earlier enough in the day, i.e. around noon, FC will rise above 10.

When my FC starts to drop more than I like, i.e. from FC 10 one day to FC 8 or so, I check my CYA. It may have dropped from 70 to 60 then I will bump it back up to 70 to stabilize my FC losses. My IC60 is currently set to 27%, the pump runs 24/7 which adds 2.5 FC a day.
(M)
How often & for how long is your autocover open? Our is typically open 3:30pm-6pm and closed the rest of the time unless I'm doing something with the pool / the dolphin is running a cycle where it cleans the water line.

Right now it's back at 20. It was rising steadily at 20 (I think) and I dialed it down to 15 and then that's when things kind of started to go haywire. I realized I need to start logging percentage changes in the pool math app b/c I can't remember.
 
How often & for how long is your autocover open?
Cover is opened every day unless I am out of the area traveling. Timing is not consistent. One day I may open it around noon and close 6:00 pm. Other days I may have been busy and didn't open it till 3:00 pm and still close it around 6:00 pm. Unless we have a late afternoon/evening swim then we might not close it till 8:00 pm. We are not consistent opening/closing the cover. However, If FC drops to 7 for any reason, I add liquid chlorine to bump it back up to 9. I go no where near the lower target range. The lower target range is my minimum. Refer to the FC/CYA chart in post #5 above.
 
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Cover is opened every day unless I am out of the area traveling. Timing is not consistent. One day I may open it around noon and close 6:00 pm. Other days I may have been busy and didn't open it till 3:00 pm and still close it around 6:00 pm. Unless we have a late afternoon/evening swim then we might not close it till 8:00 pm. We are not consistent opening/closing the cover. However, If FC drops to 7 for any reason, I add liquid chlorine to bump it back up to 9. I go no where near the lower target range. The lower target range is my minimum. Refer to the FC/CYA chart in post #5 above.
Still learning, are there reasons to have it for more hours in the day than what I’m currently doing?
 
are there reasons to have it for more hours in the day than what I’m currently doing?
Daily maintenance can not be spelled out. TFPC provides ranges of values because each pool is different and each pool owner has different circumstances in the lives to take care of their pool what works best for them, keeping in mind, the underlying principles of TFPC.

Keep your pool cover open or closed as long as you want. The pool water does need to breath to burn off CC with the UV rays from the sun. The TFP recommended ranges for pool water chemistry is contained in pool school. Bottom line, enjoy your pool.
 
Ok. Now turn it on 100% tonight and measure the overnight *gain*.

That will steer us to the SWG, or back to the CYA.
9:33pm FC - 3.8
5:41am FC - 3.2
Make 5 your new minimum. Never approach it. Then, when an unexpected loss happens (like this thread prompted), you're still covered. There is no downside in raising the target for you, besides the initial +4ppm.
 
That will steer us to the SWG, or back to the CYA.

Make 5 your new minimum. Never approach it. Then, when an unexpected loss happens (like this thread prompted), you're still covered. There is no downside in raising the target for you, besides the initial +4ppm.
Just want to make sure I’m understanding correctly. So tonight:

1. Test FC after sunset
2. Set SWG to 100%
3. Measure FC at sunrise

Is that right?
 
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You can sleep in a little, and if the test is off by 1 pm at 7AM, it'll still give us a good idea of how much FC you made.

An OCLT, on the other hand, might fail if you don't get up early enough. Ironically that will make you do it again. :ROFLMAO:
 
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So it looks like the cell isn't producing. Check the cell for buildup. If it has no visible scale, has power, and isn't tripping low flow/salt, it's likely done for. :(
 

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