Trouble Raising Chlorine

KristaM78

Well-known member
Jun 29, 2021
56
Illinois
Pool Size
11200
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Yesterday, I measured my free chlorine at 2.0 and my combine chlorine a .6. My salt reading was showing 2800. I use the Taylor K Dash 2006C test kit. My salt cell is flashing for high salt. I checked the hours on my cell and it is showing 2000 hours so plenty of life left in my cell. Yesterday evening I ran my SWG on super chlorinate for three hours. This morning when I tested I am still showing free chlorine at 2.0 in cc at .6. I am really feeling like I need to add some salt to the pool. I have a Pentair Intellichlor IC 40. My concern is is that I’ve read to go buy whatever your salt cell is saying. Any advice or recommendations would be appreciated.

the pool is crystal clear.

Alk 85-90 adjusted for CYA
ph 7.4
CH 250

Fiberglas pool
 

Texas Splash

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33,417
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You can use the PoolMath APP (Effects of Adding) to help you with the amount of salt required to increase to a new target. But be sure to test your salt level with a good kit (i.e.. Taylor K-1766) and don't just take the cell's word for it. While the cell needs to sense a reasonable salt level, their accuracy can be off.

Your FC is definitely low, so increase with liquid chlorine right away. Your CC level is also elevated. You might consider doing an Overnight Chlorine Loss Test to ensure algae isn't trying to grow.
 
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Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
22,829
Bedford, TX
Krista,

If the salt light is flashing (high salt) yet your actual salt level is only 2800, something is wrong. Most likely you have a bad thermistor inside your flow switch. Replacing the flow switch is an easy DIY fix, assuming you are out of warranty..

The cell will still run with high salt warning.

I too recommend that you run an Overnight Chlorine Loss Test.

Thanks,

Jim R.
 

KristaM78

Well-known member
Jun 29, 2021
56
Illinois
Pool Size
11200
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
You can use the PoolMath APP (Effects of Adding) to help you with the amount of salt required to increase to a new target. But be sure to test your salt level with a good kit (i.e.. Taylor K-1766) and don't just take the cell's word for it. While the cell needs to sense a reasonable salt level, their accuracy can be off.

Your FC is definitely low, so increase with liquid chlorine right away. Your CC level is also elevated. You might consider doing an Overnight Chlorine Loss Test to ensure algae isn't trying to grow.
Thank you. Yes, as I mentioned I do use a Taylor test kit for chemicals and salt. I don’t go by by sWG cell.
 

KristaM78

Well-known member
Jun 29, 2021
56
Illinois
Pool Size
11200
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Krista,

If the salt light is flashing (high salt) yet your actual salt level is only 2800, something is wrong. Most likely you have a bad thermistor inside your flow switch. Replacing the flow switch is an easy DIY fix, assuming you are out of warranty..

The cell will still run with high salt warning.

I too recommend that you run an Overnight Chlorine Loss Test.

Thanks,

Jim R.
Yesterday evening I took my free chlorine reading and it was 2.8. This morning I took it and it was too, but my pool had not been running yet this morning. I didn’t think about that until after I had taken the reading. This evening I just took it and it is 2.4 after my SWG has been running today. I currently have it running 9 AM to 7 PM at 80% output.

If I have algae growing I cannot see it.
With that being said even when I use a bag of Oxysheen or multi shock my combined chlorine never goes lower than .4

I am losing my mind! Thoughts?
 

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Texas Splash

Mod Squad
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Jun 22, 2014
33,417
Texas, San Antonio/Marion, South-Central Area
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Yesterday evening I took my free chlorine reading and it was 2.8.
Much too low per the FC/CYA Chart. I'm willing to bet you have algae.
If I have algae growing I cannot see it.
That is often the case. Algae isn't always a messy swamp of green. The inability to maintain a reasonable FC level is often the first sign.

You should be using liquid chlorine or regular bleach when you're in a pinch and need quick uplift of FC. You mentioned your Overnight Chlorine Loss Test may have been performed in error, so I would do another one to be sure. But for the remainder of the day, get the FC up with liquid chlorine to about 6-7 ppm. Even a bit higher won't hurt.
 

KristaM78

Well-known member
Jun 29, 2021
56
Illinois
Pool Size
11200
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
In addition, you should stop using the Oxysheen. Oxysheen is non-chlorine shock (MPS) and it will interfere with your CC readings. Stick to good-ole liquid chlorine or regular bleach.
Thanks you. I haven’t used oxysheen for over a month so I know my readings are good. I have been added liquid chlorine😀
Much too low per the FC/CYA Chart. I'm willing to bet you have algae.

That is often the case. Algae isn't always a messy swamp of green. The inability to maintain a reasonable FC level is often the first sign.

You should be using liquid chlorine or regular bleach when you're in a pinch and need quick uplift of FC. You mentioned your Overnight Chlorine Loss Test may have been performed in error, so I would do another one to be sure. But for the remainder of the day, get the FC up with liquid chlorine to about 6-7 ppm. Even a bit higher won't hurt.
ok. So I don’t have to SLaM? I can just add liquid chlorine to rapidly raise my chlorine to 6 or 7?
 

Texas Splash

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Jun 22, 2014
33,417
Texas, San Antonio/Marion, South-Central Area
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Chlorine
Salt Water Generator
SWG Type
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So I don’t have to SLaM?
Possibly. We were waiting for you to do another Overnight Chlorine Loss Test since the one you did a couple days ago the pump didn't mix the water. If you wish to go right into a SLAM Process you certainly can. It won't hurt, and based on the consistently low FC it's warranted. Be sure to lower the pH to about 7.2 first though. Then go back to the FC/CYA Chart (salt water tab) to find the correct SLAM FC level based on your current CYA. At that point, you would just leave the SWG off and use liquids chlorine to maintain the elevated FC level.

Speaking of CYA, what did you mean in post #1 when you said, "Alk 85-90 adjusted for CYA"?
 

KristaM78

Well-known member
Jun 29, 2021
56
Illinois
Pool Size
11200
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Possibly. We were waiting for you to do another Overnight Chlorine Loss Test since the one you did a couple days ago the pump didn't mix the water. If you wish to go right into a SLAM Process you certainly can. It won't hurt, and based on the consistently low FC it's warranted. Be sure to lower the pH to about 7.2 first though. Then go back to the FC/CYA Chart (salt water tab) to find the correct SLAM FC level based on your current CYA. At that point, you would just leave the SWG off and use liquids chlorine to maintain the elevated FC level.

Speaking of CYA, what did you mean in post #1 when you said, "Alk 85-90 adjusted for CYA"?
I will take a reading this morning. Regarding the Alkalinity. As measured by my Taylor test kit it was 110. But after making the CYA adjustment I know it is about 85-90 by subtracting approximately 1/3 of the CYA from the Alk reading.
 

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Texas Splash

Mod Squad
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Jun 22, 2014
33,417
Texas, San Antonio/Marion, South-Central Area
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Chlorine
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CircuPool RJ-45 Plus
I will take a reading this morning. Regarding the Alkalinity. As measured by my Taylor test kit it was 110. But after making the CYA adjustment I know it is about 85-90 by subtracting approximately 1/3 of the CYA from the Alk reading.
I see. There's no need to do that. We make math easy here at TFP. :) Just do your normal TA test by multiply the number of drops x 10 that it takes to get to Barbie pink, and you're good to go. :goodjob:
 
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Mdragger88

Bronze Supporter
Jun 1, 2018
2,974
Hernando, Ms
Pool Size
26000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
I do not see where u listed your cya ppm- although you have accounted for it.
At the settings you have your swg on you should be producing around 5ppm/day fc if your pool volume is accurate.
the average pool consumes 2-4 ppm /day although this could be higher in the heat of the summer with a low cya.
Fyi - you can share your PoolMath logs by tapping the gear ⚙️ icon , scrolling down to the bottom, & switching the toggle
78BF2919-80B3-4813-93B7-69DF5532A9DF.jpeg
 

KristaM78

Well-known member
Jun 29, 2021
56
Illinois
Pool Size
11200
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
I do not see where u listed your cya ppm- although you have accounted for it.
At the settings you have your swg on you should be producing around 5ppm/day fc if your pool volume is accurate.
the average pool consumes 2-4 ppm /day although this could be higher in the heat of the summer with a low cya.
Fyi - you can share your PoolMath logs by tapping the gear ⚙️ icon , scrolling down to the bottom, & switching the toggle
View attachment 370705
Ok. I have subscribed to the full version to keep my logs. I will do that!
 

KristaM78

Well-known member
Jun 29, 2021
56
Illinois
Pool Size
11200
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Possibly. We were waiting for you to do another Overnight Chlorine Loss Test since the one you did a couple days ago the pump didn't mix the water. If you wish to go right into a SLAM Process you certainly can. It won't hurt, and based on the consistently low FC it's warranted. Be sure to lower the pH to about 7.2 first though. Then go back to the FC/CYA Chart (salt water tab) to find the correct SLAM FC level based on your current CYA. At that point, you would just leave the SWG off and use liquids chlorine to maintain the elevated FC level.

Speaking of CYA, what did you mean in post #1 when you said, "Alk 85-90 adjusted for CYA"?
Ok. This morning my FC is 2ppm and CC .4. Yesterday at 4pm my FC was 2.4. I promptly added quite a lot of liquid chlorine. I didn’t measure, but certainly enough to raise several PPM. So, I suppose my next step is to measure as add enough to raise to atleast 6ppm?

also, since my salt reading with the silver nitrate kit is 2800, should I add salt after this? Regarding the flow switch, that might me an easy fix for you, but I’m not sure I can do that. Are there any videos that show how to change the flow switch?
 

Texas Splash

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Jun 22, 2014
33,417
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Ok. This morning my FC is 2ppm and CC .4. Yesterday at 4pm my FC was 2.4. I promptly added quite a lot of liquid chlorine. I didn’t measure, but certainly enough to raise several PPM. So, I suppose my next step is to measure as add enough to raise to atleast 6ppm?
Yes, you should increase the FC. Sounds like your Overnight Chlorine Loss Test didn't quite go as planned. If you do one in the future, just remember to take the first FC reading after dark or before bed, then the second test early before the sun hits the water. The SWG must be off and water must be mixed at least 30 minutes before taking water sample if the pump was off overnight.
 

KristaM78

Well-known member
Jun 29, 2021
56
Illinois
Pool Size
11200
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Yes, you should increase the FC. Sounds like your Overnight Chlorine Loss Test didn't quite go as planned. If you do one in the future, just remember to take the first FC reading after dark or before bed, then the second test early before the sun hits the water. The SWG must be off and water must be mixed at least 30 minutes before taking water sample if the pump was off overnight.
All of this process was followe with the exception of my 4:30 pm reading. However, at that point we had a storm roll in so I put my auto cover on. So I shouldn’t have lost much chlorine the rest of the evening. I will proceed with adding liquid chlorine and see where that gets me.
 
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KristaM78

Well-known member
Jun 29, 2021
56
Illinois
Pool Size
11200
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Possibly. We were waiting for you to do another Overnight Chlorine Loss Test since the one you did a couple days ago the pump didn't mix the water. If you wish to go right into a SLAM Process you certainly can. It won't hurt, and based on the consistently low FC it's warranted. Be sure to lower the pH to about 7.2 first though. Then go back to the FC/CYA Chart (salt water tab) to find the correct SLAM FC level based on your current CYA. At that point, you would just leave the SWG off and use liquids chlorine to maintain the elevated FC level.

Speaking of CYA, what did you mean in post #1 when you said, "Alk 85-90 adjusted for CYA"?
Hi. I completed the overnight chlorine loss test. I tested yesterday at 5:30 there was no sun on my pool and again at 7:20. I went from 3.2 down to 2 overnight. interestingly my combined chlorine did go down that makes zero sense to me. I went ahead and subscribed to the app so that I can share my log.
This morning I added everything I had in hand which was 42 oz of bleach. I will head to the pool store today to buy chlorine. What is my best course of action now.

 

Texas Splash

Mod Squad
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33,417
Texas, San Antonio/Marion, South-Central Area
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Chlorine
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Honestly, since your OCLT went almost 14 hours long and was "barely" over 1 pm loss, I think you are okay. That's a long time for an OCLT. I wouldn't worry about the cc level. Going down is always good. If you wish to maintain an elevated FC for today to be safe, or perhaps do one more OCLT but only for about 8 hrs or so, that's fine. But if the water is crystal clear, I really thing you are good.
 

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