refractometer

alexk3954

New member
Yay! I think I might actually be able to afford my LR in the next week or two. Now the only thing that I still need is a refractometer. Can anyone reccomend one that is decent? I don't want to spend more than 50 dollars ( but will if I have to). I was looking at the cheapest one on marine depot.com. How often do I need to calibrate it? Can I just calibrate it with RO water that I use for topoffs, as I know the salinity is zero?
 
PremiumAquatics.com has one in your price range.
I calibrate mine at every water change. It only takes a moment to drop 3 or 4 drops of RO/DI on the screen and zero the thing.
 
i use distilled water (gallon jug) from the grocery, since the r/o machine might be off if the filters are old etc.. or like me , i hafta buy it from my lfs and I dont trust em
 
I plan on buying RO from the lfs. Tourkid mentioned that he doesn't trust his lfs. Do the rest of you think that it would be safe to top-off and calibrate with RO from the lfs?

Why are some refractometers so much more pricey than others? Are they all very accurate if you keep them calibrated?
 
Drs foster and Smith sell a portable one in your range...go to their site here on Reefcentral and there is a discount code for it.
 
I think many if not most own their own RO/DI units. If you have a TDS meter, you can pretty much verify that your water is pure. That water is fine for calibration. (a good RO/DI unit is worth the investment in the long run)
The pricing of refractometers is directly related to the quality of the device. A $500 unit is far more accurate than a $50 one. Maybe not 10X more accurate but more accurate. For our needs, the inexpensive one is fine IMO, the main idea is to be consistent
 
Using the calibration solutions in Bertoni's link is a good idea. I have noticed since calibration that pure water is a bit off from their scale. I do know, however, that the refractive index matches seawater, which is more important, IMO.
 
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