boxtechAquarium Marine Test, Sea Saltwater Hydrometer, Reef Ocean Hydrometer Salinity Meter for Pool Aquarium Water Salinity Specific Gravity Test

If you are new to these, pay attention. Bubble will form on the float and they need to be shaken off (very easy). Do NOT install this in your tank or it will grow algae on it.How to use properly:1. Fill with water, knock against tank to take off bubbles.2. Repeat step 1 like 5 times3. Fill with water and read.This is calibrated at 77 degrees F or 25 degrees C. If you have cold water fish (under 25C) use google.com to find the conversion tables. it is not much of a difference, but if you are keeping very cold water expensive corals and fish... 'mightcould want to check it out.

So I bought this as a back up, I double check all my water prior to doing a water change. I have an automatic readout and a couple other plastic hydrometers like this. This thing wouldn't even register RO/DI water. Telling me the salinity was off the charts. Yes I knocked all the bubbles off with the point and tapped the sides and sat it on a flat surface. Maybe the float stick is a little to much, I'm not sure but this thing is way off.

I have brackish shirmp, so I bought this to help adjust the salinity. Thankfully I was doing very small amounts of salt so as not to stress them. However the readings on this never seemed to changed and I didn't want to risk the shirmp.So I got a bowl of water and measured it at 1.004, dumped a ton of salt and waited about 30 minutes and tested it again. Showed at a 1.012, poured it back and tried the same water and it showed 1.019, and then 1.014 and a 1.016. Safe to say this meter will be going straight to the trash and I'll be looking for a new one.

Seems useless. Tested with distilled water and it read 1.012. Not a trustworthy instrument.

I own a refractometer which is extremely accurate but I still like the convenience of just dipping a box type specific gravity meter and getting instant results.Having owned several of these from all the different manufacturers, Coralife, Instant Ocean, etc. I always found them unreliable at best. This Boxtech one has been very accurate so far and almost matches what my Refactometer says. It reminds me of the very first hydrometer I had 30+ years ago in its design and accuracy.

Off by three points. I keep my reef/fish tank at 1.023. This reads 1.029. And yes no air bubbles on it. I am returning it. Six points can kill coral or fish. Some corals are very delicate. So inaccuracy is very important.

Functional sensing is appropriate, accurate and thoughtful service. I'll buy it next time. Very good. The handwriting is clear. This one is very convenient to use, with high accuracy. There are no problems in using it. It's very convenient. It's very small. It's very delicate. It's worth buying

Just OK. If your a serious hobbyist spend a few more dollars and buy a Hanna.