Salt level reading not changing

tigerucla

LifeTime Supporter
I installed our Aquarite 940 last April. It ran great all summer keeping the salt level between 3200 and 3400. (Pool store reading was closer to 2800 at the time.) I turned it off in December when the water temp went below 50 degrees and switched to liquid chlorine.

At the end of February, I went to turn it on again when the water temp got above 50, and the salt level read 2200. I added a 50 lb bag of solar salt- no change. I added another 50 lb bag- still reads 2200. I tested the water at our local pool store- hey got 2700.

I added 100 lb salt. It's still reading 2200. Water temp is now 62.

I called Hayward- the guy I spoke to said I should clean the cell with MA. I checked the cell in Feb before I went to turn it on- no deposits. I don't see how cleaning the cell will help. His other suggestion was to take it in to Leslie's, if they have a salt cell tester.

What do you all think? Is this normal behavior given the water temp?
 

gwegan

TFP Expert
Apr 19, 2013
2,769
Sacramento, CA
You should not rely on the cell to determine your salt content. Use a salt test kit. Taylor has one. They are much more reliable. I would also clean the cell
 

pooldv

Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
25,148
FL panhandle
I don't mess with my SWG or salt level until the water is above 70° F. There are potential issues with temp correction, temp sensors, etc at lower water temps and every SWG is different. It just isn't worth the hassle to me to try to figure it out or fix it. So, I use bleach until the water is 70. It has been this way for a couple of years or more. My SWG works absolutely fine all the time when the water temp is above 70 and that is really the only time I need it to.

It takes about 24 hours for the salt to fully dissolve and mix into the water. And there is an instant salt reading and an average salt reading, the average only updates once or twice per day.
 

tigerucla

LifeTime Supporter
Thanks guys. Would it make more sense to recalibrate the Aquarite (and maybe recalibrate again when the temp gets higher), or to acid wash the cell?

Also, which is the most accurate way to measure salt level? Strips? Taylor kit? Pool store?
 

ping

TFP Expert
LifeTime Supporter
Jun 24, 2011
2,940
Long Beach, CA
Acid cleaning can clean the temp sensor inside the cell if it is scaled. I would try this first to rule out any chance of scale interfering with the sensor. Give it 5 to 10 minutes in a 10:1 or 5:1 water to acid soaking.

Taylor K-1766 is the best kit to measure for salt levels.
 

JamesW

TFP Expert
Mar 2, 2011
13,302
I wouldn't acid clean the cell unless you see scale. Acid takes off the coating on the plates and shortens the life of the cell.

If the temperature reading is accurate, the sensor is fine.

The cell does not have a conductivity sensor inside.

What do the diagnostic readings show?

As noted above, there is an instant reading and an average reading for salinity. The instant shows the current reading. The average lags behind unless you update it.
 

tigerucla

LifeTime Supporter
JamesW- that's what I was originally thinking. But it seems like most here are recommending I acid clean. Maybe they didn't notice that there are no scale deposits on the cell.

The temperature reading is accurate to within 2-3 degrees, compared to the thermometer.

To be honest, I didn't realize there was an "instant" reading. I will check that when I get home.

Thanks!
 

tigerucla

LifeTime Supporter
OK, here's the deal. I came home this evening and went to look for the "instant" reading. When I scrolled through the display, it showed "-0" after the Percentage number. (Before James@ mentioned it, I had no idea what that number was supposed to be.) So I figured I must have to turn the unit on in order to get that instant reading. I turned on the pump, and moved the switch on the SWG from "off" to "auto". After detecting the flow, the "instant" reading showed -3500. The "average" reading then quickly went up to 2800.

So the lesson I learned, which may be useful for SWG newbies in the future, is this- the first number which shows up on the display is "average" salt level, but it is not accurate if the unit is in "off" mode. I guess that's probably obvious to those of you who've been using these for years. To me, it's counter intuitive to show an "average" salt level if it hasn't actually been reading the salt level. In any case, I think all is well. I will not be acid cleaning my cell (though I did order a cleaning stand- I guess I will need to use it at some point in the future).

I realize once the water temp comes up in the summer, the "average" reading may go a few hundred higher. How high is too high to where I would need to drain water?
 

bobandsherry

Bronze Supporter
Apr 20, 2016
386
Riverview, FL
Additional lesson learned.... salt level should not drop to zero over winter or any extended period of time. The salt does not evaporate. The salt level only drops based on replacement of water. So..... if you had salt when you closed the pool you will have salt when you open it (should be same level). If you show 0 then there's a problem in the reading. Minimally, before adding salt, get a pool store to test and verify. The best would be to test using K-1766 salt test kit to verify. That said, I've just started to test with K-1766 and found my AquaRite reading agrees with test kit so I feel comfortable that my AquaRite is properly reporting the salt level, but can verify every 3-6 months.

Regarding the "0" reported as instant salinity, I also experienced same issue as you with the instant salinity reading, here's my post and also includes response from Hayward regarding the reading. Looks like you got caught in same confusion on reading as I did (especially since manual doesn't mention this). It is confusing to me why your average showed "0". Unless you had left the salt % at zero, when the cell charged for the first time the average reading should have been updated. If you had it at zero then cell never charged so therefore never had a chance to get updated.

One other lesson learned, once you add salt you need to recalibrate the average reading. Once you add salt, as I mentioned in this post:
The SWG should be left off for 24 hours once salt was added. Additionally when you add salt you may want to reset the salt reading (it's an average) by doing an update to get an Instant Salinity reading. To do this (from the manual):


  1. Slide the Main Switch to the "Auto" position.
  2. Push the Diagnostic button repeatedly until "-xxxx ppm" appears on the display.
  3. Slide the Main Switch from "Auto" to "Super Chlorinate" and back to "Auto".
  4. Push the Diagnostic button to exit.

Note that step #2 will show you want the salt level reading is at the current time, so you could also just check and see if that level is lower than the average reading being display.
To your point, you have to ensure that the salt cell is charging at the time, so temporarily turn the salt % up to 100%.

BTW - you may want to update your signature to include the salt cell detail. This will help should you ask question regarding chlorine readings and such in the forum as responses can/will vary based on use of SWG or not.

Enjoy the pool this year.
 

chawkins99

Well-known member
Mar 29, 2014
72
Gulf Breeze, Florida
Another noteworthy tip from Hayward:

If the SWG is on while the pump is off (no flow), this will cause an inaccurate average salt level.

The flow switch will prevent chlorine generation but will continue to calculate the average salt level resulting in an inaccurate read-out.
 

tigerucla

LifeTime Supporter
Thanks for the tips bobandsherry. Just to clarify, I was originally thinking the salt level was 2200 (not 0), since that's what the average reading was. (That made sense to me, since we've had a ton of rain (finally) here in California this winter.) At that time, I was not aware that there is also an instant reading. I checked with a salt strip before adding any salt. What confused me was that after adding salt twice, then checking the level at the pool store, then adding more salt a third time, that the SWG still read 2200 (what I now know is the "average" reading). When JamesW mentioned the "instant" reading, I got further confused at first when I looked and it said -0.

What I figured out is that the average reading, as well as the newly discovered (for me) instant reading, do not change until the SWG is actually generating. Just being powered on does not cause the unit to measure salt levels. I don't understand why they would have it display the level if it's not actually taking a reading. But now that I know that it does, I won't look at the readings in the future until the SWG is actually generating.

Thanks to all for your help and suggestions.
 

bobandsherry

Bronze Supporter
Apr 20, 2016
386
Riverview, FL
Thanks for clarification on the initial reading Tigerucla, that makes more sense than what I originally had thought :) Agree their display isn't as clear to understand as it could be, whoever wrote the UI should get input from actual users. The good news is your salt level is up now and you learned about the instant salinity check for next time.
 

tigerucla

LifeTime Supporter
Saying their display "isn't as clear to understand as it could be" is being rather kind. But I suppose we all learn to put up with it. I'm guessing it's been that way for a long time and that Hayward is not interested in changing it.
 

JayBauman

LifeTime Supporter
Sep 5, 2014
617
Katy, TX
After (finally!) figuring out my controls and display, I was able to make sense of my salt system. For several months after I built my pool, I stressed over why the INSTANT reading was different than the AVERAGE value in the regular display sequence. After heavy rain dilution or salt addition, it could take a week or two before both values agreed with each other. I now tend to treat this situation like I do when adding CYA: I add the calculated amount, then assume it's actually in the water, even though it doesn't show up in testing for several days.

Of all the many things that can go wrong with a swimming pool, an exact reading for my salt content is very low on the list. As long as salt concentration is high enough for the electrolyzer to be able to conduct current between the plates, all is good.