Refractometer-??? What's going on?

Maybe Im trying to much… I have mixed 125 reef tank. For last 5 years Im using Refractometers. There is many different opinions about this. With what to calibrate? RO water or Refractometer fluid. Recently I found inconsistencies. Ill try to explain it to you. I have 2 Refractometers. 1 4 years old 1 two years old. Two bottles of refractometer fluids. One old and one new ( year old). Problem. When I calibrate with those fluids I have different results in my tank water salinity. 0.024 and 0.026 which tells me fluids are bad ( at least one of them). So i calibrated them with RO water. Now salinity shows 0.027 on both refractometers. What you guys think? Any help, suggestions? It is really frustrating. I had to add that all is good in my reef.

 

Don't calibrate with RO/DI. With the fluid, I know mine reads 35 ppt at 77°F. I stick the whole bottle in my tank to get it to temp. If your house is cool or warm, this can make a decent difference.

 

+1 always calibrate with the set point closest to what you are trying to measure.

 

Yes,thats what I was doing for most the time. But my problem is that when I calibrate with first bottle my tank water salinity is different then when I calibrate with second bottle. That means one of these calibrating fluids is bad.

 

Do you have a LFS that uses a refractometer? Maybe have them double check it.

 

Im going there now…

 

The red sea refractometer auto calibrates for temperature. Might be something to look into

 

You will need a third kit.Hopefully that matches one of the other two or at least close.

 

I dont know why I didnt think about that last year when it appeared mine was off... I bought another meter and fluid... DUH