Relatively new to home brewing, completed about 8 batches most with very good results but I'm in grad school so I'm pretty much completely broke and can't afford much in the way of brewing equipment. To compensate for the lack of equipment yet my desire to do AG brewing, I've been doing AG half batches (3.25-3.5G) with a large grain sack / 20qt pot and rinsing the grain as best I can. My BG and OG measurements have been OK (about 70% total efficiency) but there is a lot of trub (small particulate matter) that hasn't settled out when I take my measurements in a thief. How severely would this be affecting my hydrometer readings?