If I was you I would spread out the tipups. Crappies really have a tendancy to school and to use different depths. If you get a tipup in one area, grab your rod and hurry over there. Pull up the tipup, catch the fish, and have another hole drilled a few feet away. Put your rod down and lower the lure/bait to the level where you got the other crappie, and you will probably catch 2 or 3 more before the school leaves. Hope this helps, and good luck!