Beds should be placed in varying depths 2-6' depths. I like elevating mine off the pond bottom to help reduce siltation process using cinder blocks and pallets. My design is somewhere on the forum archives - work very well keeping beds clean and SMB love them.

Many men go fishing all of their lives without knowing that it is not fish they are after. ~ Henry David Thoreau

[Linked Image from i1261.photobucket.com]