So, dumb mistake on my part, but I forgot to calibrate my refractometer for the last couple of brews. What struck me as odd was that my efficiency seemed to go up lately, but my attenuation apparently went way down. Lo and behold, I calibrate the sucker today and it's reading 1.5 Brix with regular water.
I guess my question is how to assess the readings I made while it was uncalibrated? My OG on those readings was only slightly above average, but FG was about 10 gravity points higher than expected. Does this mean my efficiency actually went down recently?