Using a Refractometer

[sgc0286]

Hi!
Im sure this probably sounds simple, but I just got a refractometer and I do not know how to use it. I think you just put the water on the blue face plate, but how many drops? Also does it need to be calibrated and if so how do you calibrate it?

Thanks.

 

[AMDPhenomX4]

Ok, Just get RO water and make sure it reads 0. Cover the plate with 3 drops. Afterwords clean with cloth and do tanks water.

 

[sgc0286]

okay thanks, is RO the same as distilled?

 

[CaptainAhab]

If you really want to be a stickler you would get calibration liquid and calibrate to the SG on that. Distilled and RO should be the roughly the same.. Though that depends on your RO TDs output

 

[sgc0286]

Thank you both for your help.

 

[Kurt_Nelson]

If you really want to be a stickler you would get calibration liquid and calibrate to the SG on that....

This is the calibration fluid:

Aquarium Testing Solution: American Marine Inc. 53.0 mS Calibration/Reference Fluid

In my opinion, it's more than being a stickler... it's just more accurate. My refractometer doesn't read accurate at both 1.000 (RO/DI) and 1.026 (35ppt). When I calibrate it using the calibration fluid, it will read about 1.002 when it's seeing 1.000 RO/DI water. Better to calibrate it to a standard that is closest to the tank's salinity.

 

[ryshark]

This is the calibration fluid:

Aquarium Testing Solution: American Marine Inc. 53.0 mS Calibration/Reference Fluid

In my opinion, it's more than being a stickler... it's just more accurate. My refractometer doesn't read accurate at both 1.000 (RO/DI) and 1.026 (35ppt). When I calibrate it using the calibration fluid, it will read about 1.002 when it's seeing 1.000 RO/DI water. Better to calibrate it to a standard that is closest to the tank's salinity.

I agree with this, using distilled or ro/di water is just not accurate enough, in my experience. I have had good luck with that PinPoint calibration solution linked above. For a long time I thought my reef tank was at 1.025, but after buying calibration solution I found that I was really only at 1.022.