HI salinity checker drift?

[davidcalgary29]

After my last salinity crisis, I bought a HI98319 less than a month ago. I calibrated it with one of the included calibration packets before using it for the first time, and every thing seemed peachy. I've been finessing salinity to match meter readings...and then did a water change yesterday, and noticed that my Kenya Tree and finger leather didn't look very happy at all (the acans, zoanthids, and BTA seem fine, though). I checked it with another package of calibration, and there appears to have been a 2.7 ppt drift over the past two weeks. Can that be right? I was skeptical, so used one of my other Hanna calibration packets...with the same result: the 35ppt solution was reading as 32.3. Is this large a drift over this short a time normal? Do I have to recalibrate the thing every time I use it? I've been rinsing with RO/DI solution and storing it dry, and this can't have been frozen, as I had it shipped with livestock on overnight delivery (the livestock was fine).

 

[Randy Holmes-Farley]

I'm not sure what would cause it, but it might be true. My conductivity meter (not the Hanna) was unchanged in calibration for 10 years, but the Hanna is obviously very different.

Rinsing in RO/DI, air drying, and freezing should not hurt it. It contains no fluids.

 

[Ron Reefman]

I quit using a refractometer and just got my hydrometer calibrated instead. In over 5 years it's never changed (and it's been tested a dozen times).

 

[davidcalgary29]

A very nice member here sold me a tropic marin glass hydrometer a couple of weeks ago, and I can't wait for it to arrive.