Abstract: AN AQUATIC raisable floor apparatus includes a platform and a buoyancy chamber in the platform with a top and a bottom. The chamber is closed on the top and open to the pool near the bottom. There is an air supply connected to the chamber. A valve is capable of venting the chamber to atmosphere. The platform is raised by filling the chamber with air from the air supply and the platform is lowered by venting air from the chamber to atmosphere through the vent. There is also a guide mechanism for guiding the platform as the platform is raised or lowered. The guide mechanism includes vertically extending racks. Rotatable pinions engage the racks.