Automatic Temperature Compensation Sea Water Salt Salinity Refractometer for Aquarium, 0% - 10% & 1.0 to 1.070 S.g. Dual Scale Hydrometer By Adeadvancedoptics

Very good value for the price. Especially considering the price for this hydrometer is not really that much more than the old needle float meters. ( That dont work right ).Pro'sExcellent valueIs accurate ( Best feature )Always measures the same results from the same sample2 Con's that I found with the unit I received.The adjustment to see the results is blurry when looking through the viewfinder. At the best adjustment the numbers and the line level still look blurry. However, once you can finally make it out its good and works.The second con is in the swivel pin for the cover plate. I have to fiddle with it in order to get it to sit down correctly over the testing area.Considering the cost of hydrometers I would buy this one again at the $25 price point.

Works well. Was perfectly calibrated when I received it, but planning on checking the calibration from time to time to see if it ever gets out of wack. I ordered 5 of these and 4 came in hard cases while 1 came in a soft case. I'm not totally sure why, but it seems to be a toss up whether you will get a hard or soft case? That's why I knocked off a star. I've used them for saltwater tanks measuring between 1.020-27 approximately with accuracy. I'd say it's a good price for what you get as well.

This device has been working great for several months now. No issues at all and always a clear reading. The focus adjustment knob needs a bit of work. When trying to adjust focus sometimes you are actually unscrewing the top. Could be better designed but if you are aware and are careful its not even an issue.

I had a floating hydrometer for my reef tank, but got concerned that it might not be accurate. I bought an Instant Ocean hydrometer with floating arm. Waste of money. I finally ended up getting this refractometer (and a separate purchase of Salinity Calibration Fluid - from AMERICAN MARINE INC to check the calibration).The hydrometer is really simple to use, comes with an eyedropper to collect water and a zipper case. It's perfectly accurate based on the known calibration fluid. The scale is really easy to see and understand, and there is an eyepiece adjust that gives you a good focus even if you need glasses to read. I can check the water in 5 seconds without squinting. Wiht the hydrometer i had to read the scale of something floating in the current in my tank or try to kock the air bubbles off the arm of the hopeless Instant Ocean hydrometer.I strongly recommend a refractometer vs. a hydrometer for making sure you have the right saltwater mix. Wish I bought this years ago. Will never go back.

My unit was off on slope calibration, so when following the directions to calibrate at 0% with RO/DI water, I was off by .005 when I measured a solution in the 1.026 range. As this was for a salt water tank, a difference of .005 salinity is a pretty big deal.After doing research, this is a very common problem with inexpensive refractometers. So make sure you calibrate to a solution much closer to the range you want to measure, rather than with RO/DI water, as the instructions suggest. The slope calibration on these units just isn't good enough.

If you own a saltwater aquarium, this is an essential product to make sure your salinity levels are where they should be at all times. Since my tanks have been established for some time now, I tend to check salinity when doing water changes or once a month otherwise. Some folks choose the meters you keep in the aquarium water itself, but from experience and reading the experience of others, this is the way to go. It might take an extra minute to get a reading, but you are always certain you'll get an accurate measure of what's going on in your tank.When held up to light, you get a clear reading of where you are at and can make adjustments as needed before retesting. If you are unsure about this brand or make/model, let me just assure you that it does what it's supposed to do and you will be happy with your purchase!

The hinge pin is made from steel that corrodes. This makes the glass top bind and operate poorly. Surely the manufacturer could spend a little bit more for a stainless steel pin that wont rust. Especially since this tool is intended to be used with saltwater. Seems like common sense. Mine lasted two years before I had to discard. But the item became frustrating to use after only one year.

Ordered this to check the salinity of a jellyfish tank I received as a gift. The plastic swing-arm hydrometer that came with it was not very accurate. After some research, I found that refractometers were the way to go, and while they are a little more expensive up front, they are well worth it.This one was one of the more affordable ones on Amazon. The actual unit is pretty well made and feels durable and sturdy in the hands. The accessories (pipette, carrying case) are nothing special, but adequate enough to use. Instructions were easy to follow, although there were a few grammar and spelling errors. Focus is easy and stays put. Gradient is clear and easy to read.Make sure you calibrate using distilled or reverse osmosis water. Point at a light source to clearly see the measurements.