OK, I've got a refractometer.
Two points.
1. Have you calibrated it as per the instructions ?
2. I put your reading into Beersmith and I think you've using the wrong Beersmith option. You need to select "Fermenting Wort Gravity" in th calculation dropdown box, enter 5.8 into the Refractometer Reading field and then the original OG before fermentation started (you did measure this I hope

) into the Original Gravity field. It will then give you the gravity reading. The reason for this is that the calculation for fermenting wort needs to take into account the alcohol content which changes the refraction gubbins.
