info here...
Waterbed mattresses vary in the amount of movement suited to each individual. 12 second movement is for people who like to be swayed to sleep and there is a free flow. 5 second movement is semi stable.
For better support and less movement, then a stable 3 second movement waterbed mattress is required. Or even a super stable 1 second movement waterbed mattress. For people who want no movement what so ever, the ultra stable 0 second movement waterbed mattress would be their best choice.