Instant Ocean SeaTest Hydrometer

I've never used a refractometer, some people hate the hydrometers but I personally like them. Way cheaper and once you know how to properly use it you'll get a pretty accurate reading. If you have more delicate corals or fish definitely spend the extra money and get a refractometer but if you're just setting up a new tank, it'll do the job. YOU WILL NOT get an accurate reading if there are bubbles on the needle. Just gently tap the entire hydrometer on a flat surface a few times and the needle will adjust to the correct reading.

This is the only brand of hydrometer that I will use. I have purchased this one a few times, because I broke it one way or another. They hold up well, but you cant step on them. It is accurate and lasts a long time. Just make sure to keep it rinsed and clean after every use to makesure it stays accurate. You will love it.

This is the second hydrometer of this model that I've owned (they do get erratic over time even when rinsed and stored with RO water, I think because the pivot point wears and also gets precipitate on it). The previous one read one point high, while this one is accurate.Any plastic swing-arm hydrometer will have issues with air bubbles sticking to the arm when the hydrometer is new -- that's often why people have issues with these things. I soak mine in salt water for about three days, rinsing with RO each day then refilling. That seems to remove the film on the plastic that attracts the air bubbles.Swing arm hydrometers also should be checked for accuracy. I calibrate them against a (properly calibrated) refractometer. Once I determine how high or low the hydrometer reads, I make a note of that (I use a permanent marker to note on the back of the hydrometer, e.g. "This hydrometer reads 1 ppt high"). Then I have an easy to use, accurate device to do routine checks of salinity (well, actually specific gravity). The more tedious-to-use refractometer is used for periodic sanity checks.

It was inexpensive and does its job well. But for those of you who don't already know this, you have to rinse out with normal water before and after using it with saltwater. You also have to gently fill it with saltwater and tap the top and ensure to rid the inside of any bubbles, then you'll get a relatively accurate reading of your salinity. You follow these simple rules and you'll love it! 5 stars!

In order to keep your tank healthy, you should invest on a good quality hydrometer that gives you accurate readings. This is just not one of them. I read a lot and did a lot of research and ended up purchasing this Instant Ocean Sea Test Hydrometer, but, turns out that every time I take measurements, it gives me a slightly different reading. As a beginner on saltwater aquariums, this item shouldn't have been on my list. One wrong reading can determine to lose of a fish or 2, specially if you have expensive ones.

I know there are a few bad reviews on this product, but for me it worked well like I remember. It is a mechanical measuring device, so if you're looking for an exact reading I would by a digital one. Just remember to make sure there are no bubbles of air on the needle gauge and you measurements will be fine.

Returned this item. I was setting up my tank and used the recommended amount of salt. It was reading off the chart. I rinsed it, tapped it, flicked it, soaked it in fresh water, waited for water to reach temperature. Nothing worked. After changing over 50% of the water it was barely reading down to 1.032. My tap water was reading 1.014. After reading forums I found these are incorrect a lot of the times. The forums suggested a salinity refractometer. I bought one and calibrated it with distilled water and the salinity then tested at 1.020. Way low when the hydrometer was reading 1.032. Good thing I went with my gut on this one before buying live rock. Ditch this and get a refractometer. They are awesome!!

I have a refractometer and used both for or Oysterr Education program. It was accurate with the refractometer. It has the same readings. If someone says it did not work, they do not know how to use it. pushed it down and let it rise on its one. We used it three times in the field and in lab class along with the refractometer each time. Great product.

The best hydrometer for salt tank!

Perfect item just what I needed thanks

bad quality and package

Didnt work as well as my old one. Bubbles get trapped under the needle and give inaccurate readings. Ive done everything to keep this from happening but it continues. Switching to a refractometer