I'm going to pour a new floor in the basement and to avoid having to put filler over the entire room, I thought of embedding 16 mm flex hose in the floor. That should work, right? Or should I use some special hose? 
Regular hose works fine. There is really cheap hose that isn't very good, but otherwise no special hose is needed. Step on the hose because you will do that when you are casting, if it can handle that, it can handle being cast in.
Keep in mind to fix it, it wants to float up.