Help, my refractometer isn't working

I bought the portable refractometer from that Doctor aquarium place in Wyoming and it's acting weird.

I calibrate it using their ro water and adjust the screw until it reads zero, then when I put my salt water on it the readings go below zero. How can I have less than zero salt? What am I doing wrong? :O)

 

Make sure there are no bubbles under the glass, it needs to be solid water. Is your unit ATC (automatic temperature compensating)??? These are my best guesses!!! With mine I pull it out of the box drop water on it and I'm done! No problems at all, so I'm clueless if the above things don't help!

 

Yeah, it's temperature compensating, but the bottle of calibration water says "PINPOINT Salinity Monitor 53.0mS Calibration Fluid +-1% @77F/25C American marine Inc. The refractometer model number is RHS-10ATC. No bubbles either.

 

Take down to LFS and have him check it out and calibrate for you. :-/

 

I tried!!! See what any experts have to say... Meanwhile, have a friend test for you, if you don't have any buddies with a working refractometer maybe take a sample to your lfs and see what they have to say. you may have a defunct refractometer?

 

That's sounds really weird. Never heard of that before. All I can say is you're ok because Drs Foster & Smith have A++++ customer service. They'll send you a new one, no questions asked..

 

Marty, I'm not so sure this calibration fluid has no salinity to it. My best guess is that you're using a calibration fluid that contains more salt than sea water to calibrate your instrument to zero. Have your read the accompanying literature?

Do this: Boil a pot of water with a cover, and use the condensed water from the underside of the cover on the prism of the refractometer. That's distilled water.

For all intents and purposes, a refractometer can't "not work." It has no moving parts and uses only light and known refraction of salt to yield a reading.

Start with the distilled water, and I think your problem will be solved.

Good luck!

 

I am soooo dumb! I did a search of this calibration fluid and the one complaints was that there is no instructions. Turns out it has a salinity of 35 ppt. So you have to calibrate it to that. Did and sure enough my tank water is 1.022. Thank god for google. hehe Think I will try it calibrating to 0 and to the 35 and take an average. <shrug> couldn't hurt.

Thanks for the replies. :O) Karma to you..

 

Use distilled water and calibrate it to zero. Don't knock yourself out. I don't care how "lab tested" that calibration fluid was at the factory. Although it's unlikely, that level can change and you'll never know it.

Distilled water is 0 everywhere.

 

WOW, learn something new every day!! I just calibrated mine with RO water and everything is great in refractoland!! Mine didn't come with any solutions either though, sounds like a waste of money for the company!