Hayward Omnilogic with T940 salt cell and Taylor K-1766


Active member
Apr 28, 2021
Atlanta, Ga.
The displayed value for Instant and/or Average Salt shown on the Omnilogic Chlorinator Diagnostics screen is always about 400 ppm high when compared to the Taylor K-1766 drop test.

Does the Omnilogic actually display a TDS value and not a true NaCl salt value?
Also, for salt readings:
Is the Taylor K-1766 accuracy +/- 200 ppm?
Is the Omnilogic accuracy +/- 400 ppm?

Any help appreciated.


Mod Squad
Gold Supporter
LifeTime Supporter
Jan 17, 2012
Evans, Georgia
Yup, 400.....that is within the tolerance level for the device. SWG devices actually test the salt level differently than you. Its something like the conductivity or something more technical than I remember.

Yup, the salt test kit has a variance of +/- 200.

My rule is to always go by the Taylor K-1766 and assume the device "lies". Its easier that way. :cool:

Maddie :flower:


Active member
Apr 28, 2021
Atlanta, Ga.
I just replaced my T-Cell 15 and Haywards Omnilogic is showing readings of my salt that are higher then an actual test of the water.

Test shows 3300ppm

Omnilogic shows average salt 4390 and instant salt of 3781.

Do I need to calibrate this somehow? I cannot find any info on needing to do this.

I have the same issue and Hayward tech support said that to recalibrate, try hitting the +/- button. That does NOT recalibrate! All it does is reset an existing average. I get the same exact readings that are high when compared to my Taylor K-1766. There is an algorithm of some sort that determines the displayed value. Hayward said that I need to run my pump at 2800 RPM because the salt cell plates won’t be completely covered if I run it lower. Hayward also stated that if the cell is new, it will be off by as much as 1000 ppm; and, after it’s broken in, the accuracy is only +/- 500 ppm. Is it 400 or 500 ppm? Some say 400 ppm. Moreover, Hayward stated that I should empty my pool a bit to “trick” the salt cell. Really??

I am not comfortable with what Hayward tech support has suggested in the emails.

I will absolutely NOT run my VSP at 2800 to cover the plates! The manual states to mount the cell inverted or vertical - this makes sense to me. Why tech support did not mention this is troublesome to me. I have mounted mine inverted - getting same results. I feel my plates are covered with the inverted mount. My cell is making chlorine and keeping up just fine. It’s just that the salt reading is high.

I have not found a reliable source that could confirm if the Omnilogic displays TDS or NaCl for the salt reading. I feel TFP is the best place to get this answered. If it is actually displaying TDS, then there may be no problem at all since TDS, although dominated by salt, is an aggregate with contributions from other pool chemicals.

As far as calibration, the Taylor K1766 is my choice for salt. How to get the OmniLogic to match is another, if impossible issue. For a good TDS meter/test kit, I need advice from the experts here.
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