red sea refractometer and marine depot refractometer

[ohioboy706]

I used both refractometers yesterday and came across a little problem. Red Sea was giving me a reading of 1.022 and Marinedepot refractometer was reading 1.026. I was wondering which 1 was accurate? Red Sea is new and both were calibrated. I have a reef tank and like to keep my salinity around 1.026

 

[Acro]

Hmm if they were both calibrated with the same fluid, I don't think they would show different results?

Have you recalibrated your older one?

 

[ohioboy706]

Yes I calibrated both as I was checking salinity

 

[SaltCube]

This is actually the second time I heard this with two different results... from a different person locally.

 

[Reefing Madness]

Are you using the 35ppt calibration solution?

 

[revhtree Verified Admin]

Ouch this is kinda scary! Makes me wonder about my readings!

 

[ohioboy706]

Yeah im wondering should I go with the Red Sea reading and bump it up.

 

[Igotcorals]

I personally use the Marine Depot one and I have never had any problems with it. I also calibrate with 35ppt solution..

Strange.. But maybe try calibrating with RO DI Water? Calibrate to 0 then see what results you get with both.

 

[morgan175]

Interested

 

[mike007]

I thought that the new Redsea was made specifically for testing saltwater.

 

[redfishbluefish]

I'm sure the OP calibrated with water. This is the reason you want to use calibration solutions that are closest to what you are measuring. I've seen no difference between ebay refractometers versus named brands when they are calibrated with 53.0 mS standard solution (1.026 or 35 ppt solutions).

 

[RedSeaKev]

Ok Folks, a little information for when using the Reed Sea refractometer, it is important to first ensure the instrument is calibrated with R/O water at 25c, unlike many Refractometers available the Red Sea refractometer is calibrated for use at 25C it is also important to zero check against the PPT scale as this is the more accurate, the SG scale is a simple conversion.

It is also very important to hold the Refractometer via the black grip of the Refractometer, we use a very high quality optics and temperature correction system which can skew the result by you actually increasing the temperature of the instrument.

Check out our YouTube video here Red Sea High Accuracy Seawater Refractometer for saltwater aquariums