Marine Depot Refractometer

[ShooterRick]

I just cleaned up a MD Refractometer that came with the 72 bow front deal I scored. It appears to be functioning correctly. My question is can I calibrate it with RO or is distilled water required. How much more accurate is it than the float needle type I have been using?

[Reefing Madness]

I just cleaned up a MD Refractometer that came with the 72 bow front deal I scored. It appears to be functioning correctly. My question is can I calibrate it with RO or is distilled water required. How much more accurate is it than the float needle type I have been using?

Needle types jump all over the place, you never know what your going to get. I just use my RO/Di water that is used for the tank to calibrate mine. And you'll find that they don't go out of calibration much.