refractometer help

[lisa888]

I just received a refractometer I ordered online. It says to calibrate with distilled water, so I did that. Then I tested it with some 1.026 calibration fluid that I have (bought with another refractometer from a different vendor that had spots in the prism and I sent back). I thought it should read 1.026, but it reads 1.028. Both samples were at 68 degrees. Did anyone have a similar experience? Do you think it's a bad refractometer, or bad calibration fluid? Maybe it's close enough so I shouldn't worry? By the way, my hydrometer reads .002 lower than the refractometer, I have heard this is common. Thanks for your input.

 

[huma-huma]

id re-run the test 2 or 3 times. IF you have rodi water, use that to calibrate to 0

 

[ccCapt]

The proper way to calibrate it for use in a saltwater aquarium is to use calibration fluid. The difference you see between calibrating with distilled water and calibration fluid is about right since freshwater and saltwater refract (bend) light differently. Trust the reading you get after it's calibrated with the calibration fluid.

 

[Nomadu571]

I've read that they should be seasoned by leaving them in your tank for a certain amount of time, before they are used.

 

[lisa888]

Thanks everyone. ccCapt, I will go with your advice, you seem very knowledgeable on the subject and it makes sense to me. Like everything in this hobby, so many different opinions on every topic. I read somewhere else that you should use calibration fluid, but the directions say to use distilled water. Also a rep from Foster&Smith told me to use distilled water (with the one I had to return though, a different brand).

Nomadu571, I think you are referring to a hydrometer, I have heard that you should leave saltwater in those for 24 hrs before use.