Refractometer Driving Me Crazy

[-Logzor]

Lately i've been having issues with my Marine Depot refractometer. This unit has a built in ATC (Automatic Temperature Control).

It seems that the temperature of the unit itself has a huge impact on the readings.

I think the cool temperatures have a lot to do with the problems I am having. The tank is in the basement, so it's usually pretty cool down there.

When I use the calibration solution, I typically let it sit for awhile, then calibrate. That's fine. The problem is it will change drastically. If I do it at room temperature it's one reading, if it let it sit inside the tank stand, it appears to be way out of calibration again. If I hold it in front of the heat vent I can see it change before my eyes.

The temperature difference has a major impact.

How can I know for sure my that readings are correct?

Also, does calibration solution expire, will any evaporate, resulting in higher readings?

 

[revhtree Verified Admin]

That sounds like a lot of trouble. I am not sure on those types of refractometers.

 

[Bubbabobobbrain]

Sounds to me like its time for a new refractometer. I have a tank in my basement as well as upstairs in my house and mine reads the same regardless of which tank I am checking. Sounds to me like the atc part of your refractometer is messed up. Did you drop it or something? If so that could have something to do with it.

 

[-Logzor]

I don't think it has been dropped or anything. It's probably 3 years old or so. The instructions mention it has to be calibrated in at least 68 degree room. Do yours have this instruction?

 

[-Logzor]

Has anyone tried using a "pinpoint salinity monitor"?

 

[mooo]

I always thought all refractometers were like this. Just make sure when you do calibrate your refractometer, you take note of what the room temperature is. If room temp is the same as when you calibrated it, you can be sure that what you're seeing is an accurate reading. Therefore, try not to touch the metal part of the refractometer when trying to get readings as it will skew results. I think the relationship is..as temperature goes up, readings go up aswell.