lipo voltage diff between cell

I've got this exact same thing happening to a 3s truerc pack i got last week.. cell 1 is always lower than 2 and 3.. I balance before charging, and when I take it of the charger cell 1 is low by ~.05v.. I can't balance while charging because I'm using astroflight's. when I first got the pack, cell 1 was chillin at 2.5v.. the others were around 3.5v.. I just slowly charged at 1/2 - 1C until the pack was 1/2 charged, took it off and balanced, then continued charging at 2C. so far the pack's been running great, I dunno how long it'll last though w/ that one cell.. I'm not sure how many amps i'm pulling, but the pack's only rated to 80amps =\.