refractometer

[melosu58]

anybody know of a good deal for a refractometer on the net?

[MT79]

I got the most inexpensive one from drsfostersmith.com. I'm very happy w/ it. They had it for as low as $38.00 on sale when I was looking.

[AquaReefer]

I got a nice one I think it is one they are selling on liveaquaria from ebay for $40. I love them, and My salinity was low. Like 4-5 points off from my hydrometer. I would recommend buying one.

[jasno999]

How eaxactky do they work and why are they more bennificial than a regular hydrometer

[localhost]

Basically water causes light to bend, Salt has an effect on how much it bends. All a refractometer does is measure salinity by how much the light it bent.

They are better than hydrometers because bubbles can cause bad readings on hydrometers.

[malkore]

Originally Posted by jasno999

How eaxactky do they work and why are they more bennificial than a regular hydrometer

Simply put, the light passes thru the water sample, and then a prism. distilled water will refract back at 0. Any salt or heavy mineral content will raise the final value because the added salt will refract the light before it hits the prism.

its better because:
1. its faster
2. it isn't skewed by air bubbles
3. it isn't skewed by temperature


hydrometers measure specific gravity. temperature affects this, and not all hydrometers are calibrated to the same temp, especially the more accurate bulb type. I've never gotten consistent readings with a swing arm hydrometer either.

[hisc1ay]

Originally Posted by localhost

They are better than hydrometers because bubbles can cause bad readings on hydrometers.

That's not the only reason. Especially for swing-arm hydrometers, if they're not cleaned the reading can be way off, and can't usually be calibrated. Refractometers can be easily calibrated and are very accurate.

-j

[melosu58]

Ok so I`ve got Smith and Foster and ebay. Any links.

[havefun]

I just got this one a few weeks ago and love it.

http://www.drsfostersmith.com/produc...fm?pcatid=9957

[MT79]

its better because:
1. its faster
2. it isn't skewed by air bubbles
3. it isn't skewed by temperature

Those along w/ not having to break out a level to be sure the surface you set the hydrometer on isn't skewing the reading by being uneven. Refractometers are just plain better all around-easier to use, more consistently accurate etc.
Although the Aquarium Systems hydrometers I used were only off by .001- as they advertise surprisingly- compared to the refractometer, when placed on a perfectly level surface.