Balancing Lipo

One of my Zippy's (5000 mah, 20-30C, 3S) came in with one cell about 0.10-0.15 mah lower than the other cells. When they are fully charged, they read 4.20, 4.20 and 4.11. When I charge them, I hook them up to the balancer, but that doesn't do anything to balance them. Do I need to cycle them to get them balanced? Is there a balance function? I'm using the Venom Pro Charger.