Just visited a salt pool which has had the electrolyser turned off for the winter. Last month when I checked the free chlorine was at 6.03 ppm. This time it's 9.82 ppm. No chlorine has been added and the pool temperature is roughly the same at 10 Deg C. Combined chlorine is still low. The pool is on 6 hours per day pump cycle and is kept covered. Any ideas what is going on?
Free chlorine increased in salt pool
- Thread starter Spondu
- Start date
S,
Free chlorine can't go up unless it is somehow added.. Are you sure you are testing for FC and not Total Chlorine?? (TC = FC+CC)
Tell us what you are using to run your tests..
Thanks,
Jim R.
Free chlorine can't go up unless it is somehow added.. Are you sure you are testing for FC and not Total Chlorine?? (TC = FC+CC)
Tell us what you are using to run your tests..
Thanks,
Jim R.
Hi. Thanks for your reply. As you say, I don't know of a chemical mechanism for the free chlorine to increase. That's's why I resorted to the post. It is definitely free chlorine that has been measured. I'm using a PoolLab 1.0 photometer which has always been spot on when verified against pool samples taken into a pool analysis house. I am a PhD chemist by training, hence why I am head scratching on this one. My initial thought was that somehow the electrolyser was still operating even though switched off at the control panel but that still doesn't make any sense as it would not be producing chlorine at these temperatures. I'm the only person who has access to the pool and no chemicals have been added since the autumn. The pool clearly has not gone through breakpoint as the combined chlorine is half that of the free chlorine but both values are high nevertheless. I have elected to give it a couple of weeks and then recheck but is still very weird.
Shirker
0
- Jul 2, 2014
- 749
- Pool Size
- 19000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
- Jun 22, 2014
- 47,790
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Welcome to TFP! 
Very odd indeed. Perhaps a pic or two of your equipment pad and updating your signature with your pool and equipment info might give us a bit ore insight to your scenario. Be sure to include your test kit in that signature. Were any other chemicals added to the water back in August before closing for winter?
Very odd indeed. Perhaps a pic or two of your equipment pad and updating your signature with your pool and equipment info might give us a bit ore insight to your scenario. Be sure to include your test kit in that signature. Were any other chemicals added to the water back in August before closing for winter?
Shirker
0
- Jul 2, 2014
- 749
- Pool Size
- 19000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Not sure what test kits you have available to you in France. I assume probably not the TF kits that are popular here in the US. I don't have any experience with the optical kits. Do they use titration? Is there a way to calibrate it? A picture of the test kit and the labels of your reagents might be helpful too.
S,
I suspect that something is causing the FC test to read higher than it actually is... (We know the FC can't actually go up, so the test result must be wrong..)
Let's see if @JamesW knows what that might be...
Thanks,
Jim R.
I suspect that something is causing the FC test to read higher than it actually is... (We know the FC can't actually go up, so the test result must be wrong..)
Let's see if @JamesW knows what that might be...
Thanks,
Jim R.
Hi. The PoolLab 1.0 is a German photometer widely used in Europe and has proved to be both accurate and reliable. As a photometer, it uses tablet reagents which are dissolved in a 10ml water sample. I will send photos later.
The only chemicals added were hivernage and anti-alg, nothing else. The electrolyser is supposedly inop so the pool is hand dosed as necessary but it hasn't required any to date.Welcome to TFP!
What was the original CC and what is it now?
What are the ingredients of these chemicals and how much was added?
That was my first thought so I tested again carefully to make sure I wasn't having a DOH moment, but I'm always willing to believe that it is 'operator error'. I'm going to repeat the test with a different test technique to double check
Hi there. I've taken over from a previous pool operator who added the chemicals so I cannot be certain of the dose added. Hivernage is essentially ethylene glycol to prevent water from freezing and anti-alg is a biocide used here to prevent algae growth.
That's very unlikely. Do you have a reference for that?
Were the chemicals added before or after you did your first test?
What was the initial CC reading and what is it now?
Here's a you tube video showing the use of the photometer...https://youtu.be/GhdcbArqz5s
The chemicals were added back in October 2020. Since then no chemicals added. The CC has remained steady at under 1 ppm
Were the chemicals added before or after you did your first test?
Are you saying that you just pour ethylene glycol into the pool to prevent freezing?
It's highly unlikely that ethylene glycol would be in pool chemicals. Where did you get this information?
Here is the link to the product...https://www.mariusferrat.fr/produits-de-traitement/15251-anti-algues-5l-aquapure-3661578034216.html
That still does not tell us what was added or when it was added relative to your tests.
You need to know what you're adding before you add it.
You need to be more clear in what information you're providing if it is going to make any sense to anyone.
Details matter.
What exactly was done and when?
You need to know what you're adding before you add it.
You need to be more clear in what information you're providing if it is going to make any sense to anyone.
Details matter.
What exactly was done and when?
Shirker
0
- Jul 2, 2014
- 749
- Pool Size
- 19000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
The product description says that it "Kills all bacteria in the pool" but I can't find an MSDS (manufacturing safety data sheet) for it. Does it contain Chlorine or some other sanitizer?
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