Oh Em Gee! I've got the same one! lol. All you've got to do to calibrate it, is only put a drop of water on the glass part, then close the sunlid and make sure it spreads all the water out on the lens. Then use the screwdriver it came with, and see that little black dot on the top? That rubber piece comes off and theres a small hole in there. After you put the screw driver in there, look into the eye piece and turn the screwdriver until the white line is exactly at 0. Wa-la you've calibrated it. But like roka said, either do this with ro/di water or with calibration fluid. I practiced calibrating mine with regular water, so thats why i know how to do it. If you do need any help JOM20, just PM me!!