Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
Re the treading water: For the OW course I recall you weren't allowed to float. The 10 min. requirement was quite strenuous. But for DM I read that you can float, and even "fake drowning" (assume that means you can intentionally slip below the surface to rest?). This would seem to make the 15 mins. a piece of cake, even with the last 2 minutes hands out of the water. Any comments?
As for the tread,i am a sinker. I can sit on the bottom of the pool with a 3m suit on with all my gear off.