how to Calibrate a refractometer

[ducati1212]

So I got my new marine depot refractometer and It comes with a screw driver to calibrate it but no instructins. How, when, where and why do you calibrate one.?

Also to use you just drop salt water on and look through it will be half blue and half clear and that line is the SG.??

What do you do after use to clean.? just wipe it off

[drummereef]

Just put a few drops of distilled or DI water on the lens and calibrate to 0. The furthest line to the bottom. I calibrate every couple of months. The color difference, the line that it makes, is the salinity. Just wipe with soft cloth when done.

[abugs1985]

I'm paranoid about mine...i calibrate it with distilled water everytime i use it, wipe it dry with a lens cloth and then test my tank water.

[ducati1212]

great thanks.

Its reading 1.025 and my hydrometer was reading 1.023

[ducati1212]

I just tested it with RODI water it it read 0. so it must have came calibrated.

[abugs1985]

hydrometers are worthless...always have that refractometer on hand!

[graveyardworm]

An article regarding calibration. http://www.reefkeeping.com/issues/2004-06/rhf/index.php

[ducati1212]

thanks great article. Makes me wish I did not get a $40 one. Should have went with a top of the line one if for nothing else to make me feel better

[drummereef]

<a href=showthread.php?s=&postid=8100310#post8100310 target=_blank>Originally posted</a> by ducati1212
I just tested it with RODI water it it read 0. so it must have came calibrated.

They usually come callibrated, but better to be safe than sorry. At least you know how to do it now, right? :)