Tumbleing large Items

Hello every one, I am attempting to tumble hollow ware. I have an old
rectangular vibratory style machine. So far the cut down process has
been a dream and the burnishing phase a nightmare. I am now trying
2mm balls porcelain and cylinders. My work just does not seem to
float in the media. With only two items in the machine they settle to
the bottom and bash one another. Thanks, Nicole