I set them on a 4'x6' x 1'' thick rubber horse stall mat. the floor anchors work fine (for legalities) as it real doesn't go anywhere. Those totes will work good too as soon as the water freezes inside. I suppose if you didn't want to use the mats, you could frame it in the bed with a half dozen 2x6 boards edge up.Davidb56 - How are you tying down the blocks? I'm considering two IBC totes full of water for some weight so I can load and unload them myself. The cargo tie downs don't look like they could take the load but I may be wrong.