Jandy low temp / low salt warning

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kmellp said:
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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The only thing that matters is time and percent. RPM doesn't matter. RPM just needs to be enough to satisfy the flow switch.
 
kmellp said:
Got it. I’ll try running the pump at its original setting of 1750 RPM for 24h at 70% chlorination to see where it’ll get me in terms of FC.
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That TruClear in your pool of 22k gallons will add 5.1 parts of chlorine if you run it at 100% for 24 hours.

At 70% it will add 3.57. Your pool probably uses 2-4 parts per day so you may not see any rise at all.
 
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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I was wrong on this I thought you had the AquaPure. The TruClear doesn't add as much.

AquaPure max chlorine gas output: 1.25lbs
TruClear max chlorine gas output: .93lbs
 
kmellp said:
In that case, should I be running it at 100% for 24h to maintain 5-11 FC range? I'm a bit struggling to understand why it was set to 40% by the previous owner and they didn't seem to have any issues with chlorine.
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Not really, once you reach your target (adding liquid will be quicker) you only need to generate what you use each day. SWCGs are for maintenance levels of chlorine.

It could have been they were running a low (or no) CYA. Might have been supplementing with liquid or pucks. Could also have been they were using other magic pool store potions to mask not having enough chlorine.

Who knows but whatever their reason, you are doing it correctly.

That SWCG is a bit undersized for your pool. We recommend twice the volume for the SWCG. That one is rated at 35k gallons and you have 22k gallons. If you ever replace it, get the AquaPure 1400.

FC/CYA Levels
 
PoolGate said:
Not really, once you reach your target (adding liquid will be quicker) you only need to generate what you use each day. SWCGs are for maintenance levels of chlorine.

It could have been they were running a low (or no) CYA. Might have been supplementing with liquid or pucks. Could also have been they were using other magic pool store potions to mask not having enough chlorine.

Who knows but whatever their reason, you are doing it correctly.

That SWCG is a bit undersized for your pool. We recommend twice the volume for the SWCG. That one is rated at 35k gallons and you have 22k gallons. If you ever replace it, get the AquaPure 1400.

FC/CYA Levels
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I really appreciate your detailed answers!

I added a bit of liquid chlorine to get me to ~7 ppm FC and from there I’ll keep experimenting with the chlorine percentage / pump run time to maintain that level.
 
kmellp said:
Forgot to ask: should I be concerned with higher than recommended salt concentration (4300 vs 3600)? I would guess it will be consumed over the course of the season and shouldn’t be a huge issue.
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TruClear specifies 3000. It doesn't have an upper end where it will complain. 4300 is fairly high for sure you don't want to add any more. It doesn't get consumed per se but via splash-out it will go down.
 
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@PoolGate

My (somewhat mild) struggle continues: I'm having hard time maintaining recommended level of FC even with higher chlorination setting. Right now it's set to 80% with pump running for 15 hours at 1800 rpm. Yesterday, it was at 3.5 in the evening and this morning FC was at 2. At first, I thought it's the CC that should be high, but that's not the case and its value is sitting at 0.5 ppm. It is getting hot here in Vegas, but not extremely hot (~90'F), so I wouldn't expect that to significantly affect chlorine disintegration yet.

I run the pump from 7 AM to 10 PM.

What I did:
1. Checked CYA - all good, 70 ppm.
2. The cell is clean (as I mentioned, I replaced it less than a month ago).
3. Added liquid chlorine today to get FC level to 6 ppm.

Not sure why FC is dropping like crazy. I could run the chlorinator at 100% for longer (24h?), but I would think that shouldn't be necessary just to maintain the level.
 

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.93lbs/day x 16oz =14.88oz/day of chlorine gas max (running at 24x7x100%)
14.88oz/day in 22k gallons = 5.1 FC/day
5.1FC / 24hours = .2125 FC/hour
.2125FC * 15hours = 3.1875 FC
3.1875FC * 80% = 2.55FC/day

So you are adding 2.55FC per day running at 80% for 15 hours. This is not enough chlorine to cover your daily usage which is why your chlorine is dropping.

Most pools use between 3 and 4 FC per day. That SWCG is undersized for your pool. Generally you want a SWCG that is rated for twice your pool volume.
 
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PoolGate said:
.93lbs/day x 16oz =14.88oz/day of chlorine gas max (running at 24x7x100%)
14.88oz/day in 22k gallons = 5.1 FC/day
5.1FC / 24hours = .2125 FC/hour
.2125FC * 15hours = 3.1875 FC
3.1875FC * 80% = 2.55FC/day

So you are adding 2.55FC per day running at 80% for 15 hours. This is not enough chlorine to cover your daily usage which is why your chlorine is dropping.

Most pools use between 3 and 4 FC per day. That SWCG is undersized for your pool. Generally you want a SWCG that is rated for twice your pool volume.
Click to expand...

If that’s the case, should I completely replace it or maybe run it at 100% for some time + liquid chlorine and then replace it? I’m curious why such a small SWCG was installed in the first place.
 
You have a VS pump. Find the lowest rpm that the SWCG will work and run it 24/7.

Pool builders are not real good at understanding what equipment to install. When the Truclear dies, get an Aquapure 1400. Unless you do not have automation, then look at Circupool systems.
 
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kmellp said:
If that’s the case, should I completely replace it or maybe run it at 100% for some time + liquid chlorine and then replace it? I’m curious why such a small SWCG was installed in the first place.
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I would just run it longer at a higher percent. 100% for a day (24 hours) and see what you get.

Builders do not really understand much about pool maintenance.

To get a better SWCG if you want to stick with Jandy (works with your automation), you'd need to go with the PLC1400. That will run you probably $3k-$4k installed. The SWCG you have is entry level and known to be fairly unreliable.
 
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