Milwaukee MA887-BOX Digital Seawater Refractometer - Professional Salinity Tester for Aquariums, Marine Biology & Saltwater Fishing | Waterproof & Durable Hard Case Included

I own an aquarium maintenance company and need to make saltwater often. One day, I accidentally dropped my Marine Depot refractometer into a batch of freshly mixed saltwater which corrupted the internal meter, rendering it useless. I went to my backup refractometer but couldn't calibrate it because the calibration screw rusted away. So I decided to try out this digital refractometer. Let me tell you, this thing is awesome! No more adjusting that little screw that rusts. No more looking for a bright light source to see the refractometer reading and no more adjusting the eye scope for visual clarity. This digital meter is accurate, stays accurate, reads easy and fast. I recommend you buy it with the hard plastic case to keep it protected. You won't be sorry.