Salinity differences between ICP and Home

[Randy Holmes-Farley Verified Community Expert]

I just ordered a TM Hydrometer. How would I go about checking its accuracy? Especially if I am questioning the results of my refractometer.

Make the hydrometer standard here using a scale:

Reef Aquarium Salinity: DIY Calibration Standards

 

[REEFRIED!]

So I got the TM hydrometer. I haven’t checked it with the table salt method, however it shows almost exactly what my refractometer shows. So maybe ATI is off with their two readings? The next ICP I do in a few months I am going to switch to Oceamo. We will see what they say

 

[ShakeyGizzard]

I see that precision is needed when testing for salinity especially in the controlled environment of a reef tank. We have always warned of rapid salinity changes to our tanks and recommend gradual raising or lowering. But lets ride out to the Great Barrier reef , test the salinity after days of fair weather. Now lets throw in 2 days of torrential down pour of rain. I know the water movement will be downward for the cooler water (rain) but the effect it will have on salinity during the storm has to be horrendous in shallower water during the duration of the storm. Then after the storm passes the salinity will rise at a rapid pace also. My question is : have the negative effects of this been documented ?