How do I know when it’s time to replace the cell?

[mjc123]

My cell is 4 or 5 years old. This season, everything started out fine - SWG read 3200 and happily chugged along. Over the last couple weeks it started reducing the salt reading until the low salt light started flashing, then came on full.

in terms of salt, I tried to satisfy it by adding another bag. Test strips (about 5 of them) all say the salt level is around 3500 and the fact that I can faintly taste it supports that. So it’s not actually a salt too low issue.

ive tried recalibrating it- but the instantaneous reading starts at about 2500 or lower and ticks down from there. Last night I took the cell out and inspected it- there was a small amount of scale on it but generally clean. Nonetheless I did an acid cleaning on it, and it bubbles away for 5 mins or so and stopped. When I poured out the acid it was faintly black tinged- not sure if that’s normal as I haven’t personally cleaned it before.

Anyway, rinsed it off and threw the cell back in, salt reading is still coming in below 2200 and the cell won’t generate, so I threw liquid chlorine in until I can sort it out.

As a new cell will cost me $650ish, I want to be sure the old one is truly done first. When they reach the end of their life is it normal for them to just go from working to not over a week or two? Or is it normally a long slow degradation? Could this be another issue? Any other suggestions?

thanks!

 

[ping]

The cell has reached its end of life and needs to be replaced. When the reported salinity drops below the actual salinity you know that the cell is on its last legs. Some pool shops have cell test stands that can determine if the cell is dead.

 

[bobandsherry]

I wouldn't trust the test strips. There's a test kit for salt level, get that and you'll know what your salt level is.

 

[bobandsherry]

Also, which way is the bend in your salt cell, is it up or down? If up, turn so it's down. I had similar issue with my cell, been installed with the bend up by pool installer for 2 years. This year i was getting some really strange reads similar to yours. Turned the so bend was down and all fine now.

 

[bobandsherry]

And lastly, kind of surprised you only have a T-9 for a 25k pool, cell is slightly undersized for pool your size. If you need to get a replacement get the T-15.

 

[mjc123]

And lastly, kind of surprised you only have a T-9 for a 25k pool, cell is slightly undersized for pool your size. If you need to get a replacement get the T-15.

Likely the same reason most people would. T-Cell rating > pool size. Without having visited this forum first, I imagine most people would pick the first one rated larger than their pool size.

But yes, replacing it with the t-15 would be the plan. Not cheap here in Canada though. $700 all-in is the cheapest I’ve found so far

 

[bobandsherry]

My pool builder informed me, so I was just cruious if it was your decision or pool builder on cell size.

Anyway, just looked on Amazon.ca and see the T-15 for $610 CDN$ ($468 USD).

 

[JamesW]

What are the diagnostic readings?

 

[mjc123]

My pool builder informed me, so I was just cruious if it was your decision or pool builder on cell size.

Anyway, just looked on Amazon.ca and see the T-15 for $610 CDN$ ($468 USD).

I bought the house/pool in November 2017, so I'm not sure how the decisions were made - and yeah, that's the cheapest I could find too. add 15% tax and that's where I got $700 from. Also, with respect to your other posts: understood that the test strips are not necessarily accurate, though I have a high degree of confidence that the salt level is over 3000, which is still different than the cell reads. As for the bend in the cell being up or down I'm not sure what you mean. Mine is mounted vertically and the cable was coming out of the top. I tried switching it around (cable out the bottom) and see no difference in the readings.

What are the diagnostic readings?

As I'm sure you know, the numbers are constantly changing, but when I flick the switch from "Off" to "Auto" and click through the diagnostic screens I see:
80
26.5 to 27.3
2.29 to 2.97
52p
-1600 to -2200
AL-0
r1.59
t-9

 

[JamesW]

Probably time for a new cell. I would recommend the T-15.

For a horizontal installation, there might be a small difference in production from bump up vs bump down due to air trapped in the cell at low flow with bump up. At good flow, the production should be equal. For vertical installation, there should not be a difference in cell direction.

 

[mjc123]

Wanted to follow-up on this - thanks everyone for the insight and advice. My new T-15 arrived today. Plugged it in and it started working right off the bat. Instant/average salt reading went straight to 4000, which is exactly what the strips indicated it was. I drained about 1' of the water and am in the process of refilling it with fresh water to drop the salt down a bit, but regardless, the cell doesn't seem to mind the high salt reading (no "high salt" indicator light on). Anyway, thanks a bunch!

 

[JamesW]

Make sure that you change the cell type to T-15.

As long as the amps are less than 8.0, the high salt indicator will stay off.

High amps depend on the salinity and water temperature.

 

[mjc123]

Make sure that you change the cell type to T-15.

As long as the amps are less than 8.0, the high salt indicator will stay off.

High amps depend on the salinity and water temperature.

Yup, changing the cell type was the first thing I did. Good to know about the amps