Salt Cell On It’s Last Legs?

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revitup

revitup

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Nov 30, 2019
871
Pawleys Island, SC
Pool Size
8500
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
My salt generator settings have been pretty consistent year to year for 5 years. The max setting needed to generate the required chlorine has been 40% in the middle of the summer. Hayward T-15, 8500 gal. This year I was at 55% by the end of April. I have never cleaned the cell or even looked inside so I was hoping that it had calcium build up that was inhibiting chlorine generation. Took it off, it’s as clean as a whistle inside. The only other reason the generation rate would be down is because it’s on the way out right? Seems like 5 years is pretty short lived though considering how easy it’s been run. Anything else I can look at that might be the cause?
 
What is the Instant Salt reading from the SWCG versus an actual salinity using a K1766 test kit?
 
3000/3400 is 0.88.

Lots of life left. When that ratio gets to 0.75, try switching the system to a T9. It will get you some time to get a new cell.
 
mknauss said:
3000/3400 is 0.88.

Lots of life left. When that ratio gets to 0.75, try switching the system to a T9. It will get you some time to get a new cell.
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What explains the need to run so much longer to produce the same chlorine? That .88 ratio isn’t any different than I’ve seen in previous years.
 
The AquaRite uses the performance of the cell to determine salinity. For each cell (T-3, T-5, T-9 OR T-15), Hayward knows the performance of a properly functioning cell at each temperature and salinity combination. The higher the salinity and/or water temperature, the higher the performance (chlorine output).

To get the performance of the cell, divide the instant salinity by the actual salinity. If the ratio is less than 75%, it's time for a new cell. For example, 2,000 (instant salinity) ÷ 3,600 (measured salinity with a test kit)=56%. Check the cell and clean it if necessary. If that doesn't work, it's time for a new cell.

There is no separate salinity sensor in an AquaRite. There are six wires going to the cell, two white, two black, one red and one blue wire.
 

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rev,

Almost ever time I think my cell is not producing enough FC, it has been because my CYA has drifted a little too low.. For me anyway, I can tell the difference between 60 and 70 ppm of CYA.

I suggest that you check it out.

Thanks,

Jim R.
 
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+3. On the CYA. The April showers weren't affecting me and then *one drop* too much tanked my CYA last week. I only realized it when the cell wasn't keeping up. I could tell from how clear the CYA tube was while filling, that it was going to be much lower than I thought it was.

I passed an OCLT before raising the CYA, because alage may have crept in with the FC loss.
 
Newdude said:
+3. On the CYA. The April showers weren't affecting me and then *one drop* too much tanked my CYA last week. I only realized it when the cell wasn't keeping up. I could tell from how clear the CYA tube was while filling, that it was going to be much lower than I thought it was.

I passed an OCLT before raising the CYA, because alage may have crept in with the FC loss.
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I check CYA every couple of weeks. I was 70 less than a week ago.
 
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So, passed the OCLT. Also did a ‘daily chlorine depletion test’, a DCDT, or whatever you want to call it. Pump off, cell off, liquid chlorine. I’m using about 2.5 ppm FC per day right now. At 55% my cell is supposedly is producing 4.7 ppm per day (10 hrs run time). The cell is definitely underperforming. Still no idea why that would be except it’s on the way out. Do these things die slowly like this?
 
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Do an overnight gain test to rule out the UV / CYA. If it underperforms at night, it's the cell.
 
I had the same issue with my cell this year, except mine was only 3 years old. At the end of last year I did notice I had to run the cell harder but I figured my CYA was starting to drop and I was losing more to the sun. It was already September and I didn't want to waste CYA while I waited for the water to cool below 60 when I close.

I opened later than I wanted and had the start of a swamp forming. I completed a SLAM and turned on the cell after I passed an OCLT. This time of year I usually run the cell at 25% for 12 hours a day but I was losing chlorine even with the cell at 100%. I brought the pool back to SLAM level and passed the OCLT three nights in a row, so I was confident the pool was clean. When I ran the cell overnight I was only gaining 1ppm which I would due to the sun the next day. The cell looked clean but I decided to clean the cell with vinegar. When that didn't work I tried cleaning it with MA.

Over the weekend I installed a new cell and it's holding chlorine while running for 12 hours at 25%. This is my first cell replacement. It seems like the cell took about a month to go from fine to not being able to keep up.
 
wireform said:
Pump needs to remain on or atleast 30 minutes before test or else the testing is skewed.
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I performed the test over 4 days and averaged the chlorine depletion. I mixed the pool pretty thoroughly after adding liquid chlorine with a brush and by running my robot vac for 2.5 hours. I’m confident my numbers are accurate.
 
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