I mix up my own 35ppt solution, use store bought distilled water not RODI for calibration. I use the Milwaukee and occasionally a refractometer. Calibrate before every use, it takes 5 seconds.So. I picked up a Milwaukee MA887. I've had it for a week and a half and finally calibrate and test last night. It reads 1.030. I break out the Hanna, it reads 1.026. I get out the refractometer, zero it with RODI, and it reads 1.030.
I'm working on end of year reviews this week for my teams, so once that's done and I recover, I'll go through and recalibrate the Hanna and test the reference solution with the other two instruments and see what's going on. I might even have a hydrometer somewhere in the basement if the scale for brewing will work for salinity...
The only real issue not caused by overcrowding for my tank had been my RFAs bring generally unhappy and a couple cases of BJD of the past couple months...
One thing with the Milwaukee, make sure you have plenty of ambient lightning. I was showing my daughter how to use it once and our shadows threw it off by about 8, so I knew something was wrong.
Other than that I haven't had a problem with it, I also have an ATO and mix my new SW to the exact same salinity, my tank rarely deviates even 1ppt.