What are you using for weight? I'm guessing you have all your weight in one spot. Have you tried spacing out your weight by using split shot or something? You could put a small split shot just a few inches above the bait, then 2 split shot 6 inches above that, 3 split shot 12 inches above that as an example. You'd probably need to experiment with the placement, but it should allow the bait to stay below the float better.