Review on 🌊 AquaticHI Aquarium Refractometer: Accurate Salinity & Specific Gravity Testing with Automatic Temperature Control by Ashley Brunner

I got a refractor and immediately went to my seawater tank and put water under the lens from above, closed it and looked through the end and saw the graph, but it did not change Salt or fresh water, I tried adjusting it with a screw but nothing happened. Please help me if there is any other customization. Through the glass of the side I can see the scale and when I turn the adjustment screw it goes to 20 and to 40 but no change in salt water or distilled water