Refractometer calibration

[m3rcfh]

Hi all
I was looking for some expert opinion on a refractometer calibration issue.
I got a new refractometer today and used a 35ppm calibration fluid to make sure it was okay, but I reads 30ppm out of the box. I tried tightening/losing the screw, but it will only got as far as 30 ppm or less, even when the screw comes completely out.

Can it be a defective refractometer or is there anything obvious I missed?

Thanks

 

[Big G]

Is it possible you got a refractometer made for making beer? It has a different scale to read for Brix.

 

[m3rcfh]

It did say marine aquarium on the product description, and it has salinity on the visor... but it was a 20 bucks refractometer from amazon, so everything is possible!

 

[Big G]

Do you have any mixed saltwater to double check the calibration fluid is ok? If it's in the ball park, clearly then the refractometer is either mislabeled or defective.

 

[Pivitol]

It did say marine aquarium on the product description, and it has salinity on the visor... but it was a 20 bucks refractometer from amazon, so everything is possible!

I bought one of those from Amazon also, I couldn't read the scale. Returned it and bought a Milwaukee, I love it.

 

[mjlash22]

Purchased the one from BRS. Works great, calibrated fine.

https://www.bulkreefsupply.com/refractometer-for-reading-salinity-with-calibration-fluid.html

 

[five.five-six]

I bought one of those from Amazon also, I couldn't read the scale. Returned it and bought a Milwaukee, I love it.

I bought the Milwaukee digital and never looked back.

 

[Gareth elliott]

I use the aquatichi refractometer w/led from amazon. Have no complaints. What light source are you pointing towards? Perhaps try reading pure r/o water? Dont calibrate to that but at least give an idea what light and angle need to hold to view the scale since should not be 30ppt. Then repeat that light and angle with the calibration fluid.

 

[m3rcfh]

I use the aquatichi refractometer w/led from amazon. Have no complaints. What light source are you pointing towards? Perhaps try reading pure r/o water? Dont calibrate to that but at least give an idea what light and angle need to hold to view the scale since should not be 30ppt. Then repeat that light and angle with the calibration fluid.

I think I got a bad refractometer... just tested with RO water, and it reads about 5ppm below 0ppm. Adjusting screw is completely lose and it won't go up to 0...

 

[Gareth elliott]

I think I got a bad refractometer... just tested with RO water, and it reads about 5ppm below 0ppm. Adjusting screw is completely lose and it won't go up to 0...

That stinks
Amazon is pretty good at returns so least that.

 

[Big G]

I think I got a bad refractometer... just tested with RO water, and it reads about 5ppm below 0ppm. Adjusting screw is completely lose and it won't go up to 0...

I bought mine on Amazon. There were at the time a large number of these from a variety of sources. Some apparently are made cheaply from plastic. But they all looked similar. Had to weed through all the postings and found the one that is made of aircraft aluminum. Works great. Here's the link from last year, don't know if it's still the good one or not. Best to read current comments from purchasers. Hope this helps.
https://amazon.com/gp/product/B005ES6MOQ/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1