Having trouble deciphering the actions of my salt cell

[eqbob]

I'm having a bit of a mental quagmire in understanding my salt cell's actions recently.

Basically, when water temp hit ~65, I kicked the cell percentage on and up. I then added a gallon of bleach to kick FC way up so that I could be sure to be operating at a high level if something was wrong as the cell was 'turned back on'. I've done this every year, just as a protection deal.

So several days ago, FC was at 16 and salt cell was at 25% Water temp has been between 68 and 70. Salt cell reads 3150, Salt test (Taylor) reads 3200. CYA at 50.
I wanted to test that the salt cell was really pouring in the chlorine if necessary, so I kicked the cell to 80%
We had several days of sun, then rain, then sun, then wind. FC has never dropped below 12.5, so there's obviously been some production, but at 80% on an IC40, and 12K pool, I'd expect FC to be climbing because that's way more output than it needs even on the brightest summer day.

So is the failure of a salt cell gradual or wham...all of the sudden? I have found a potentially applicable discussion here but there was no real consensus as to if the failure is sudden or over time. Maybe it is variable?

I did take the cell off and look for scale and there's a few granules right at the end of about 2 blades, but the rest is clean.

I can't shake the spidey sense that the cell should be performing higher (with the metric being a rising FC) than it is.

Pool was installed July 2012, so salt cell would now be in it's 4th year.

Thoughts?

 

[ping]

I suggest to run an OCLT tonight and rule out organics consuming the chlorine.

Some cells do fail slowly but you will usually see lower salt readings than the actual amount.

 

[Gecrabill]

I just had a similar issue. I have a goldline/aquarite system. I had a day with slightly lower chlorine. I checked the swg control panel, but all looked fine. But after cycling through the control panel and through both polarities, I concluded that one side of the cell was failing. ( low salt numbers on one polarity) but the average salt was fine. Either way, my answer is, yes it can be a gradual decline.

 

[cowboycasey]

most all SWG manufacturers say that lower temps will create less output, I bet the temp is just a little lower than you think or lower than the SWG likes, once the temp goes up a little it might kick up the output...

 

[eqbob]

I had the chance to do an OCLT last night and it was 0 loss, so I think we can rule out organics. I know lower temps create lower output, but I know what my water temp is, and it has generated at that temp in other seasons.

- - - Updated - - -

I just had a similar issue. I have a goldline/aquarite system. I had a day with slightly lower chlorine. I checked the swg control panel, but all looked fine. But after cycling through the control panel and through both polarities, I concluded that one side of the cell was failing. ( low salt numbers on one polarity) but the average salt was fine. Either way, my answer is, yes it can be a gradual decline.

Not familiar with that cell, but what does both polarities mean?

 

[JamesW]

Since you're getting a salt reading with the IC40, I'm assuming that you have EasyTouch or IntelliTouch. Check diagnostics for the chlorinator.

 

[eqbob]

I have. They're all good. Salt levels good.

 

[JamesW]

How many hours per day does the pump run?

 

[eqbob]

How many hours per day does the pump run?

12. Not because of the chlorine needs, but because I like the sconces. So an IC40 that can produce 1.4# per day running at 80% for 12 hours should produce 0.56 pounds, which if you estimate an equivalency to 9 ounces of chlorine gas, would be a rise of 2.2 in FC, via PoolMath.

 

[JamesW]

Typically, if the cell has a problem, it will show up in diagnostics. It would be nice if all SWGs gave amps and volts like the AquaRite. That makes it so easy to see if it's working.

While generating, there should be tiny Champaign size hydrogen bubbles coming out of the returns. You could always rig up a power monitor in line with the power supply to the salt system to see the volts and amps. If they're good, it's working.

9 oz of chlorine gas in 12,000 gallons raises fc by 5.6 ppm.

 

[pooldv]

My IC40 never seems to act right until the water temp gets up to around 70, then it works great. I gave up trying a couple of years ago. I just turn it off at 70 and use bleach.

 

[eqbob]

Typically, if the cell has a problem, it will show up in diagnostics. It would be nice if all SWGs gave amps and volts like the AquaRite. That makes it so easy to see if it's working.

While generating, there should be tiny Champaign size hydrogen bubbles coming out of the returns. You could always rig up a power monitor in line with the power supply to the salt system to see the volts and amps. If they're good, it's working.

9 oz of chlorine gas in 12,000 gallons raises fc by 5.6 ppm.

Definitely not seeing 5.6 for sure! I must have had the gallons set wrong in poolmath.

I don't know what a champagne sized bubble is? ��

Also wouldn't know how to hook up a power monitor to the cell, assuming I even had one. ��

Guess the smileys from my iPad didn't come through. First one wa soup posed to be a thinking smiley and the second a winking smiley.

 

[JamesW]

Hydrogen bubbles are very small. The diagnostics should indicate a problem if there was one.

Try comparing fc of water from a return to water in the general pool.

 

[ping]

Covering the basics, make sure the SWG has enough flow at all the pump speeds that you have programmed.

When you get a chance, check the cell every 30 minutes or so during the day to make sure it is running at all times. I would switch the output to 100% when you do this test. The cell might be bad when the polarity of the cell switches.

You will see small bubbles coming out of the returns when the pump is running at a slow speed and the SWG is on. You might not notice them if the pump speed is high enough to breakup the bubbles before they enter the pool.

You might try to crack open the downstream union on the cell to get a water sample. This water should measure a higher FC amount than the pool does.

 

[eqbob]

Ya'll have lost me on this polarity of cell switching thing. I can certainly check on it periodically (more than I already have) to ensure the lights are on, but I have no understanding of the discussion of polarity switching. Flow indicator light is green at all speeds, including lowest. Power and salt lights are green as well. At this point in time, the cell has slightly north of 15,000 power hours on it, given a 12 hour run time and 1,271 days since conversion to salt. Producing hours are different since that number does not take into account the percentage setting.--I don't know if they estimate cell life on producing hours or power hours.

I'm not sure about the direction to crack open a downstream union on the cell. If you do that, you're definitely going to break the cell??

I always take water in the direct vicinity of a return...just works out that way as to where the returns are in the pool.

I looked for bubbles, but did not see any. Could have been doing the time the cell wasn't actively producing, although honestly, I have never seen bubbles come out of my returns.

 

[ping]

The polarity of the cell is a built in cleaning design to help the cell get rid of any scale that develops. You can not check for this, it just happens every so often while it is on. I'm not sure of the cycle time for the cell to switch its polarity, that is why I suggested to check it often. Some cells will stop working when the polarity switches because the plating on the cell blades has worn out.

I should have said loosen the SWG so water will leak at the SWG union. In no way do you ever want to break a cell.

I always take my water sample away from any return, I don't want the test influenced by water that is just returning to the pool.

For now, pass on the bubble test as a determination if the SWG is working.

It is the producing hours that count towards the life span of the cell. They have designed an amount of chlorine to be produced by the cell and on average they last 3-5 years depending on many factors.

I'd let the water warm up a bit more before you decide that the cell needs to be replaced. You might want to start shopping for a good price on a new cell and have it ready to go when it's time.

 

[eqbob]

Thanks. Sounds like solid advice. I have found an IC40 for 523 at some unknown pool supply company on the web and I've got a bookmark for a supplier via Amazon for 580.

 

[JamesW]

The IntelliChlor tries to keep the amount of chlorine produced constant by keeping the current (amps) constant. It does this by increasing the voltage to the plates when the water is colder or has less salt or the cell is wearing out. If the voltage needed to keep the current constant gets too high, the cell will shut down with a warning.

As long as there is no error displayed, the cell is probably producing the correct amount of chlorine.

 

[eqbob]

The IntelliChlor tries to keep the amount of chlorine produced constant by keeping the current (amps) constant. It does this by increasing the voltage to the plates when the water is colder or has less salt or the cell is wearing out. If the voltage needed to keep the current constant gets too high, the cell will shut down with a warning.

As long as there is no error displayed, the cell is probably producing the correct amount of chlorine.

I'm not sure how you can arrive at that conclusion given that the FC isn't, or just barely is, rising on an 80% setting. It is keeping constant or incremental increase. But not the 5.6 increase per day. I will let the water warm up more and see what happens then.

 

[JamesW]

One way to tell how much chlorine is being made is to check the power usage. If the volts and amps are correct then it's working. If it's not producing and the system is not throwing an error message, then there is something wrong with the system.