YSI 556 MPS (multi probe system). Anyone have experience with this meter?000000

[Townes_Van_Camp]

Does anyone have any experience with this meter? I have full time access to one. The readings that I get from the probe are all a bit lower than I get from hobby grade equipment. The YSI unit is maintained and calibrated by a USGS Hydrologist/Geologist(my wife)

Should I be chasing any of these numbers? I am going to adjust my temperature accordingly.

TEMP
lab immersion thermometer (alcohol) - 78
556 mps - 74.75

PH
50$ Milwaukee probe - 8.1 (calibrated 7 &10 before each use)
556 mps - 7.6

SG
Amazon refractometer (calibrated w/ ocean water) 1.026
556 MPS 50.0822 = 1.025


Other parms I don't check with hobby equipment:
DO 6.3mg/l 90.6%
ORP 80.9

 

[SPR1968]

I can’t answer the question but I can bump the thread to see if we can get you some help

 

[Randy Holmes-Farley Verified Community Expert]

Do you and your wife use the same fluids for pH calibration? One is off, and I expect the difference is not the brand but the calibration. Temp corrections may also play a role.

Is it actually giving seawater salinity, or brine salinity? I'd personally stick to conductivity unIts (mS/cm) for it since that is what it measures. You can do any conversions yourself. It also must be doing a temperature conversion that may be set incorrectly for seawater, etc.

Temp should be fairly easy to check. Put the temp probe in a glass of ice water and see if it reads zero deg C.