Jandy low temp / low salt warning

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kmellp

Member
Apr 21, 2024
16
Las Vegas
Hello,

I'm very new to everything pool related, so bear with me :)
We have a 22,000 gallon salt water pool. I've been testing the water using TFP Pro kit and balancing the chemicals. Everything seemed pretty easy to do until yesterday.
TC level was very low (~1PPM), so I set my chlorinator to 60% for that day (I run the pump for ~8 hours). However, that didn't help and TC level barely changed.
I turned on the boost mode (100% chlorination) and that raised TC to 3PPM over 10 hours.
I then noticed my Jandy pump display showing "Low temp / Low salt", so I checked the salt level: it's at 4300 ppm, which I know is somewhat higher than it should be. The air/water temperature is ~74F, so definitely not cold enough to stop producing chlorine. I then checked the salt cell and it was pretty clean with no calcium buildup.
I guess my question at this point is what I should be checking.

Thanks!
 
Is it the Aquapure or the Trueclear? If the Aquapure check the temp on the LCD panel. That's what it uses not the pool temp and it doesn't care about air temp. It sounds like it might be the tri sensor. 4300 shouldn't read as low salt.
 
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mknauss said:
Welcome to the forum!
For the FC loss, I would suggest you do a Overnight Chlorine Loss Test. You need a proper test kit to do that. What test kit are you using?
For the SWCG, lets ask @PoolGate as he has experience with Jandy equipment.
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool
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Thanks for your response and links, I’ll definitely check them out.

I’m using TF-100 test kit. I haven’t had any issues balancing other chemicals though. In terms of chlorine, CYA is at 80 ppm, so I’d think this should prevent chlorine disintegration.
 
PoolGate said:
Is it the Aquapure or the Trueclear? If the Aquapure check the temp on the LCD panel. That's what it uses not the pool temp and it doesn't care about air temp. It sounds like it might be the tri sensor. 4300 shouldn't read as low salt.
Click to expand...
It’s AquaPure TruClear. Previous owner was using AquaLink and their phone app, so that’s what I’m using as well to control the system.
 
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mknauss said:
It does not. You still lose 2-5 ppm FC per day. Right now I am at about 3 ppm FC loss per day.
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Got it. Chlorine production was set to 40% when I first started using the system and it’s been running like that for some time. When I noticed low chlorine value a few days ago, I set it to 60% for a day, but that didn’t seem to help. As I said earlier, I boosted production and now it’s around 3 ppm.
 
mknauss said:
With a CYA of 80 ppm, you need to get your FC up to at least 6 ppm fast. Add liquid chlorine. Never let it fall below 4 ppm.
Click to expand...
Got it.
I’ve seen a pretty lengthy discussion here on how long people let their filter/chlorinator run and it seems that lots of people are running it 24/7. I’ve been running mine for 8 hours at 1750 rpm. After reading that thread I was thinking about switching it to 24/7 and reducing rpms to 1300 so that chlorine production is more even over the course of day. I imagine the only way to tell if that’s a better option is to try it out.
 
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kmellp said:
It’s AquaPure TruClear. Previous owner was using AquaLink and their phone app, so that’s what I’m using as well to control the system.
Click to expand...

Those cells always fail prematurely. I would go right to a new cell. If you get 2-3 seasons out of it you are doing well.
 
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PoolGate said:
Wherever it is cheapest. And for sure that cell would be dead by now.
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Makes sense.
To be clear, the only way to tell that the cell is dead is by observing how much chlorine it produces, right? Like there are no other explicit indicators.
Also, would that explain why I’m seeing “low temp/low salt” warning or is that part unrelated?
 
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kmellp said:
Makes sense.
To be clear, the only way to tell that the cell is dead is by observing how much chlorine it produces, right? Like there are no other explicit indicators.
Also, would that explain why I’m seeing “low temp/low salt” warning or is that part unrelated?
Click to expand...

It depends. The TrueClear doesn't give as good of diagnostic errors as the AquaPure but it gives some errors. See your manual below.

 
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A quick update: after running chlorinator at 100% for 1.5 days, I’ve got FC to 5 ppm. CC is at 0. That’s with the old cell. The new one is coming today, but I wonder if I should keep using the old one for now - looks like it still has some life in it.
 
kmellp said:
A quick update: after running chlorinator at 100% for 1.5 days, I’ve got FC to 5 ppm. CC is at 0. That’s with the old cell. The new one is coming today, but I wonder if I should keep using the old one for now - looks like it still has some life in it.
Click to expand...

For sure I would keep it going until it drops.

That cell should add 6.8 FC each 24 hour period at 100% though.
 
PoolGate said:
For sure I would keep it going until it drops.

That cell should add 6.8 FC each 24 hour period at 100% though.
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Hello,

I figured instead of creating a new thread I'll ask here.

As I mentioned above, I replaced my SWC with a new one and at first I thought everything was good. I then change my pump RPM to 1400 and let it run for 16 hours. Noticed that over the course of 3 days my FC level was around 2 ppm (which, as we established, is very low and barely meets the minimum for my CYA level of 70). I turned on the boost mode for 10 hours and in the morning noticed the FC level jumped to 5. CC at any time over the course of these experiments was never over 0.5 ppm. Right now I've been running the pump at around 2000 rpm for 12 hours with chlorination set to 80% and I'm still at 2.5 ppm FC. The water is clean and there are no signs of anything bad (although I'm not sure if I'm supposed to notice if it's just getting started).

A few questions:

1. I've read a few posts that say that it's impossible to tell the "ideal" RPM for any given pool without experiments. Based on the info above, my understanding is that running the pump at 1400 RPM is not enough to introduce enough chlorine into the pool and I should experiment with higher RPM values. Did I understand that part correctly?
2. Why can't I get over that bare FC minimum without boosting? I know the previous owner was running the pump at 1750 RPM and chlorination was set to 40%. I did notice he left a bunch of liquid chlorine, which I image he might've used during winter (it's not super cold here in Las Vegas, but cold enough to stop / reduce SWC production) and not as a replacement for SWC, but who knows.
3. My other chemicals seem to be in order (tested daily, all within recommended level). My salt is at 4300 ppm, which is higher than recommended, but I would think it's not the root cause of this low FC, right?

Is there something I'm missing here?
 

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