Salt Levels

[DONNIE]

My Taylor salt kit says my salt level is 3400ppm. I tested it 3 times over the weekend and always come up with 3400ppm. I added the salt Friday and it is completley dissolved and the pump has run 24/7. My PoolPilot Dig-220 says salt is @ 4500ppm. Am I missing a setting or adjustment?

Donnie

[chem geek]

The salt level reported by an SWG is usually just a calibrated measurement of conductivity, not an actual measurement of chloride level (measured as ppm salt) that your test kit measures. The conductivity of your water will vary based on temperature (higher conductivity at higher temperature) and the SWG might not be compensating for that in its display (though usually this problem is seen when the water is too cold and the SWG incorrectly reports a too low salt level). Also, the conductivity will vary based on other ions in the water such as those that come from TA and CYA levels or from sulfates in the water and the SWG may not be adjusting for that if such levels are different from whatever "standard" level that was expected.

Just out of curiosity, what kind of acid do you use -- Muriatic Acid or Sodium Bisulfate? Do you use any sort of non-chlorine shock (potassium monopersulfate)? You could have sulfates in your water that are providing more conductivity but are not measured in the chloride (salt) test kit, but the difference of 1100 ppm seems quite large.

Richard

[DONNIE]

I use muriatic acid and BBB right now. Though I have the salt in the pool the water is 48F so I have just been adding a little bleach to keep it right. Everything SEEMS fine. Water is crystal clear. Will the SWG pay any attention to that number and adjust output or will it go by my manual settings?

Donnie

[nater]

I also have a DIG-220. Right now my water temp is around 47, so the control panel has dropped cell output to 1%, and the salt reading is 300 ppm lower than my Taylor test kit results, which I trust. As Richard says, typically cold water will give you a lower reading than actual.

If you're just setting up your system, you may need to "calibrate" the cell. This is done by taking several measurements and then manually entering the value into the Control panel. See your manual or the Poolpilot web site for more detail.

I'd trust your manual test results for salt level for now. Keep the BBB method in place until you get closer to swimming temp. By then you can trust the Pool Pilot display to be closer to reality and do the calibration. Hopefully PoolSean will see this thread and add the expert opinion.

[Poolsean]

You all are too good and can just as well replace me. The feedback are all correct. The AutoPilot salt display is temperature compenstated so it should remain fairly consistent, and is based upon a true thermistor type temp reading. As Nater said, go through the MAINTENANCE menu to SALT CALIBRATION and adjust the display to your test results.

[DONNIE]

Thanks guys. I saw in the owners manual where it states "contact the factory for calibration solution". I'll try to adjust it this weekend through the maintainence menu.

Donnie