I bought one of these for setting up my conductivity probe, just for giggles after calibrating my probe I ran a few drops on my Milwaukee digital refractometer, ran consistently at 1.018SG. I thought my refractrometer was off so I checked it against my tank 1.026, RO 1.000, and the calibration soluton 1.025). opened a second one from the same lot and same readings.... no wonder why my probe given bad readings.
stick with the Milwaukee, much better investment.
It does what it is for.
I used other brands Conductivity Calibration Solution to calibrate my Neptune Apex Conductivity Probe. The probe did not calibrated correctly (many trails). The reading would be higher (60 ppt) then what it actually was (35 ppt). I decided to order Neptune Systems Conductivity Calibration Solution. My conductivity probe is now back online.
Get Multiple with your New Controller
You will want to double check, and if you should happen to misunderstand and miss the fact that you need to calibrate in AIR first, you could contaminate this while reprocessing, and wish you had another. You can make your own if you have the right equipment and experiment, and I do, but I want lab-grade references at some point.
You will want more than one with your new system.
Don't pinch pennies now.