Refractometer help

[reefkeeper1]

Having problems with my refractometer not giving me a reading for my fresh r/o + salt mix
When I mix my water for water change I get no reading but if I use 0 ing fluid or test my tank water I get normal readings please help I'm lost for answers

 

[dedragon]

this is very odd. How are you calibrating the refractometer? Proper calibration needs 1.0264 calibration solution

 

[reefkeeper1]

My refractometer comes with 0ing fluid not 35 fluid

 

[Randy Holmes-Farley Verified Community Expert]

My refractometer comes with 0ing fluid not 35 fluid

That doesn’t mean that is a correct procedure, but it might be.

which brand of refractometer?

 

[reefkeeper1]

Aquarium solution
H2ocean

 

[reefkeeper1]

Found out that if the salinity is over scale it will show up like this

 

[Randy Holmes-Farley Verified Community Expert]

If you mean this device, then yes, it can be calibrated with pure fresh water, or with a 35 ppt standard.

https://www.theaquariumsolution.com/product/3034/123
Using a 35 ppt standard will verify if it is malfunctioning, or has some other issue that makes reading your seawater properly.

 

[Jasongtr]

I calibrate my H2ocean one with RODI with no problems

 

[spawn79]

That is very strange. As far as calibration fluid goes it's generally more accurate to use a solution that's as close to the parameters of the substance being tested. Some testers can vary in accuracy when the reference solution is so much different than the solution being tested. Might not be much but it can be different.
In this case I have no idea what the heck is up. Never seen a refractometer that just doesn't show anything..... Make very sure that there isn't any air bubbles on the prism is a good start I guess.

 

[dedragon]

It is still weird that it doesnt show anything, is this a new refractometer or one you have been using for a while that has now just started to malfunction?

Found out that if the salinity is over scale it will show up like this

You would have had to dump a lot of salt in to get over most refractometers scales. I would try calibrating with 35 ppt calibration solution and then checking the results again

 

[redfishbluefish]

I'd like to take a step back and ask how you are making fresh saltwater. I ask because of your comment about over-scale not showing anything. If you are just dumping in salt I could easily see you being way off the target salinity, and this not showing up on your refractometer. To approximate my target salinity I use three cups of salt for every five gallons of RO/DI water. This gets me very close to the target salinity where I now use my refractometer to dial in the exact number.