Help calibrate refractometers



Valuable Member
View Badges
Jan 28, 2020
Reaction score
Review score
+0 /0 /-0
Los Angeles
Ok so I have a Milwaukee refractometer, a Hanna electronic salinity meter, two regular refractometers, and a apex with salinity probe.

I have three different calibration fluids: 35ppt that came with Hanna. A BRS bottle of 1.025 ppt and another bottle of 1.025.

I have tried to calibrate all 5 devices and all get different readings. Between 1.022 and 1.026. I now have no idea which one is closest to correct and can’t seem to get any of them to be consistent.

is there a reliable calibration fluid I can trust? Or how can I know for sure which is correct?

side note- can Milwaukee be zeroed with rodi? Or does it have to be distilled water? I tent to Trust the Milwaukee the most but now I’m questioning my self.

is this common or am I just making this a bigger deal then it really is lol.
Champion Lighting & Supply


Active Member
View Badges
Aug 18, 2016
Reaction score
Review score
+0 /0 /-0
I tried all brands of standards and got different results on all of them. I have 3 refractometers and a conductivity meter. I used Randy's diy standard (different formula for the type of meter) and got much better readings. Then I found accurasea natural seawater standard and it works for all the types of meters!!! Works great and guess what? Randy's DIY matches it exactly. So I'm sticking with it.

What is your most favorite type of shrimp for your reef tank?

  • Peppermint Shrimp

    Votes: 4 1.9%
  • Banded Coral Shrimp

    Votes: 15 7.2%
  • Snapping or Pistol Shrimp

    Votes: 22 10.5%
  • Harlequin Shrimp

    Votes: 16 7.7%
  • Scarlet Skunk Cleaner Shrimp

    Votes: 64 30.6%
  • Blood Red Fire Shrimp

    Votes: 51 24.4%
  • Sexy Anemone Shrimp

    Votes: 14 6.7%
  • Camel Shrimp

    Votes: 1 0.5%
  • Other (please explain)

    Votes: 5 2.4%
  • NO shrimp in my tank

    Votes: 17 8.1%
Go to for high end corals!