I've been trying to macerate a deer skull. It's been about 3 weeks. I'm useing an aquarium heater but it's not keeping a consistant temperature thrughout the bucket of water. The water at the top is rughly 90 degrees but the temperature at the bottom is very cold. Any suggestions? Its in the smallest bucket I can find to cover the whole skull. I would like to use a large bucket to do multiple skulls in.