Salinity Refractometers?

C

Capthlp

Ok, I am moving to the next level of accurate parameter readings and I am considering the purchase of a Salinity Refractometer. A quick search of the internet reveals several models and prices. I've seen them as low as $40 and as high as $200. Most of the LFS are selling them for around $100. I know prices doesn't make the meter so I am wondering what brand and model most of us are using?

When comparing the $40 online price to the $100 online priced device I see no difference in functionality. I figured I better run this by the forum before I make my choice.

http://www.northcoastmarines.com/refract.htm $40

http://www.marinedepot.com/ps_AquariumPage~PageAlias~thermometers_refractometers_hydrometers_captive_purity_refractometer.html $89

You input would be appreciated. I am sure the other online retailers will have similar pricing and models, the above were just two that I was using for comparison.

Thanks,
 
I bought an inexpensive model and it works fine. I believe some are probably made specifically for salt water and some for other media, but either way its' best to calibrate the things every once and a while. Calibration should be done at the preferred salt level. Some people calibrate to a zero TDS RO/DI water and that's fine for the lower end but you want accuracy at the intended level, this is especially true for refractometers that were made to a different spec then ocean water.

Ashlar will usually proved a calibration service at the meeting but if you can't get to them I suggest you buy some calibration fluid that is know to be correct for calibrating refractometers as I believe some of the calibration fluids are for probes. Hope Ashlar chimes in, as he is far more knowledgeable then I am on the subject.
 
RFH found a happy coincidence in that the pinpoint salinity monitor calibration fluid which has a specific conductivity _also_ has a refractive index the same as sea water- 35 ppt (sg 1.0264).
 
I'm happy with my Milwaukee MR100ATC. They're around $70 - $80 on line. I asked Scott to calibrate my new refractometer and it was off by a little bit.

Mark
 
I bought mine from a group buy a while back. I don't remember the brand. But it's black with an adjustment screw, easy to read scales, and an adjustable eye lens for focusing.

I'm happy with it.

It's been calibrated twice...at a frag swap and a meeting I believe. Mine was good right out of the box, but many need slight adjustments.
 
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