So, I've decided that my Christmas gift to myself will be a refractometer. I'm ready to ditch the hydrometer. Any recommendations? I can get one at Marine Depot or DFS for around $40. Or I've seen them on E-bay (RHS-10ATC) for $20 - $24. The one on E-bay actually looks the same as what Marine Depot is offering. Or has anyone gotten a controller and have a spare one for sale?