Calibrating refractometer

[kratos1028]

I just got a slightly used refractometer that didn't come with the screw or calibration fluid. The guy said its ok to calibrate using tap or ro water. Another person told me it will give me a false read if I calibrate using tap water and not the solution. Is it ok using tap water or do I need the solution?

 

[ColaAddict]

At the minimum u need rodi water, but It was posted here before that that has given people false readings. You really need a calibration fluid. U can buy that online

 

[rako1]

I have checked mine with calibration fluid and ro water I get the same reading

 

[Tgunz127]

The directions on my refracto say DO NOT CALIBRATE WITH WATER. I would only use the solution

 

[FishBeard]

DI should read 0, tap is unreliable for calibrating. Solution is best and relatively cheap.

 

[MMreef]

I only use calibration fluid. I tried RO/DI and distilled water and it gave me reading few points lower than with calibration solution. For fish only tanks, I think calibrating with water is ok,but with sensitive SPS I would not take chance.

 

[Smitty]

I've personally used ro water to calibrate mine...with no negative readings.

 

[KeishaKornbread]

If it has no screw, how will you calibrate it?

 

[kratos1028]

I was using the tip of a knife to help me calibrate. I'll use ro and see how it compares to tap. I'll probably swing by a lfs this weekend and get the fluid.

 

[ColaAddict]

I think you mean your missing the little screwdriver, not the screw. U can get those little screwdriver from hardware store or eyeglass store

 

[kratos1028]

yup, it has the screw, just no screw driver. Using the knife isn't too bad. I also checked to see how much off it is calibrating using tap and RO water and it was the exact same at 0 when I was checking them.