What probe do you trust more?

[Reef Jedi]

I just spent a while calibrating my new Hanna digital salinity pen and also my apex salinity probe.

Hanna = 34.7 ppm

Apex = 35.8

What probe would you trust? I also have a refractometer and just calibrated that. That basically shows right at 35ppm

Can fish or corals tell the difference between these numbers? Or did I just fall down a rabbit hole I don’t need to go down. If I follow the Hanna then I want to slightly increase salinity. But if I follow the apex then I need to go down slightly. If they were closer I feel I wouldn’t be so conflicted.

Overall what would you trust to run your salinity numbers from?

 

[Saltyreef]

Tropic marin high precision hydrometer. Use it once. Sharpie calibrate a cheap deep six hydrometer and use it everytime. Mic drop.

 

[winxp_man]

Another Tropic Marin vote. I use a 500 ml cylinder to get readings. Has yet to let me down. Although high temps will wreck the hydrometer. Don’t ask how I found out.

 

[Gumbies R Us]

I’m also going to say tropic Marin or a Manila salinity checker!

 

[EnterName]

Hanna = 34.7 ppm
Apex = 35.8

HI98319 has an accuracy of ±1ppt

I couldn't find the accuracy of the Apex probes, but 35.8ppt - 34.7ppt is just 1.1ppt, so both probes could very well be within their expected accuracy range. I would say both appear to be operating correctly.