Big divergence between measured salt level and what the SWG reports

[cheezedawg]

I’m measuring around 3200ppm, but the salt cell is only reporting 2100ppm. I just went and bought fresh salt test strips but got the same result.

My next step is to acid clean the SWG- could that cause this discrepancy or is the SWG just going bad?

 

[pjt]

I just went and bought fresh salt test strips but got the same result.

Use a K-1766 with a stirring device. Test strips are junk.

My next step is to acid clean the SWG

Does your cell actually have calcium buildup? Acid cleaning is the last resort.

SWG How It Works - Further Reading

www.troublefreepool.com

 

[mknauss]

Can we assume you have an IntelliChlor SWCG?

Might be a failing thermistor in your flow switch.

Pentair Intellichlor ICXX SWG - Further Reading

www.troublefreepool.com

 

[ManiacalMama]

I notice a bigger difference between the salt test and the onboard sensor when the water is cold. I haven't turned on my swg yet (about to do it today), but I expect to see it show a low level. In the summer when the water is 87 degrees it tends to get within a few hundred of my test results.
OP, you and I live in the same general area, so I'm guessing your water temp is near 60ish degrees right now?

 

[cheezedawg]

Can we assume you have an IntelliChlor SWCG?

Might be a failing thermistor in your flow switch.

Pentair Intellichlor ICXX SWG - Further Reading

www.troublefreepool.com

Yes IC40

 

[cheezedawg]

I notice a bigger difference between the salt test and the onboard sensor when the water is cold. I haven't turned on my swg yet (about to do it today), but I expect to see it show a low level. In the summer when the water is 87 degrees it tends to get within a few hundred of my test results.
OP, you and I live in the same general area, so I'm guessing your water temp is near 60ish degrees right now?

Yes water is around 60. I can heat up the spa water to see if that changes anything.

 

[cheezedawg]

Use a K-1766 with a stirring device. Test strips are junk.


Does your cell actually have calcium buildup? Acid cleaning is the last resort.

SWG How It Works - Further Reading

www.troublefreepool.com

Thanks- salt is the only thing I used strips for but it’s always been close enough. I’ve never seen it 1000+ ppm different than what the SWG reports.

 

[Newdude]

Thanks- salt is the only thing I used strips for but it’s always been close enough. I’ve never seen it 1000+ ppm different than what the SWG reports.

That's all fine and dandy *until* it reports a 1k difference. Then there is no way in h - e - double hockey sticks you are tearing out the flow switch per a test strip.

Test with a k1766 and go from there.

 

[cheezedawg]

I heated up my spa to 80 degrees and now the salt cell is reading 3200ppm- looks like it is just struggling with the lower water temp. Everything lines up. The water is a bit colder than when I normally start trying to open the pool. Weird cold weather. We’ve been swimming in March in some years in the past.

 

[ManiacalMama]

I heated up my spa to 80 degrees and now the salt cell is reading 3200ppm- looks like it is just struggling with the lower water temp. Everything lines up. The water is a bit colder than when I normally start trying to open the pool. Weird cold weather. We’ve been swimming in March in some years in the past.

Was it generating when it was reporting 2100?
BTW I started up my SWG today and it was reporting 2700 when my k1766 test gives me 3400.

 

[cheezedawg]

Was it generating when it was reporting 2100?
BTW I started up my SWG today and it was reporting 2700 when my k1766 test gives me 3400.

It was not generating. I’m adding liquid chlorine to SLAM now anyway to get rid of some algae