Apex Salinity Calibration and TC factor

[mike550]

First off a huge thanks to @K7BMG for pointing me in the right direction and to @eag for the great guide on calibrating salinity. I followed the guide and I’m very happy to say that over the past 48 hours my salinity readings seem to make more sense.

So now that I have a salinity probe that seems to be working I’d really like to get this dialed in a bit more. Currently the probe is reading 35.5 and my Hanna is measuring 33.4. I’m pretty confident in the Hanna reading as it was recently calibrated and someone else confirmed my measurements vs their refractometer. My current TC factor is 2.1. Is this something where I can just change it (maybe 2.2) and see where things go?

Also — can someone confirm that now that I’m using a TC factor (that’s not 0.0) I don’t need to recalibrate if I change it?

Thanks in advance.

 

[WIReefer]

@SuncrestReef

 

[SuncrestReef]

This post explains everything you need to know about salinity probe calibration and temperature compensation: https://www.reef2reef.com/threads/a...ex-salinity-calibration-and-tc-factor.718971/

 

[mike550]

This post explains everything you need to know about salinity probe calibration and temperature compensation: https://www.reef2reef.com/threads/a...ex-salinity-calibration-and-tc-factor.718971/

@SuncrestReef thanks for your reply. That's the post that I followed to get my salinity probe up and running -- thanks @eag But what I can't figure out is how to "dial in" the TC to make it match what I'm reading on my Hanna. Over the last 24 hours, the Apex averages 35.6 and my Hanna is measuring 33.4. I realize that 2 ppt difference isn't huge, but it would be comforting if I could get both of them closer to a match.

 

[SuncrestReef]

@SuncrestReef thanks for your reply. That's the post that I followed to get my salinity probe up and running -- thanks @eag But what I can't figure out is how to "dial in" the TC to make it match what I'm reading on my Hanna. Over the last 24 hours, the Apex averages 35.6 and my Hanna is measuring 33.4. I realize that 2 ppt difference isn't huge, but it would be comforting if I could get both of them closer to a match.

A difference of that amount is unlikely related to TC, but probably caused by air bubbles trapped inside the probe. Try fully submerging the probe and inverting it upside down under water and tapping it. You’ll likely see a few bubbles escape and your reading suddenly change.