Moveable floors enable an otherwise deep pool to operate at multiple water depths all the way up to zero inches to allow for flexible program opportunities. This often proves to be cheaper than having a separate body of water, especially indoors.
Typically, three different types of floors are on the market: hydraulic ram floors, scissor jack floors, and pneumatically balanced moveable floors.
Hydraulic ram floors are probably the most frequently installed floors in the United States. The piston shaft acts as both the load bearing column and the lifting mechanism for the pool floor. The advantage of these systems is that they are relatively simple lifting mechanisms with the capability of lifting very heavy loads. These floor systems tend to be small because the piston shaft must be two times as deep as the pool depth. Also, the structural load of a large pool floor tends to necessitate several lifting pistons, thus making other pool floor systems economically advantageous. A disadvantage of hydraulic floors is that the pistons need to be at least as tall as the depth that the floor is intended to traverse. Depending on the size of the moveable floor, up to eight small hydraulic pumps may be needed, though most will utilize two or four.
Hydraulic pistons are still used for scissor jack moveable floors. But with the structural advantages of the “scissor jacks” under the floor, the pistons don’t have to be nearly as tall as they do with hydraulic ram floors. These floors use collapsed hinged trusses to act as the load barring component of the lift system. A hydraulic piston expands the truss and raises the pool floor. By using leverage to its advantage, this system requires shorter pistons to lift the pool floor. Suppliers for this style of floor are limited and very often, price and servicing dictates other methods are preferred.
Pneumatically balanced floors are used frequently outside of the United States. Pneumatically balanced floors travel up and down using a combination of buoyant floor structures and ballasted tanks. Operators lock the floor in at the desired depth. The floor is interlocked into tracks recessed in the pool wall where these floors are locked into place. This style of floor is generally seen as the most inexpensive and with the compressed air / ballasting systems.
In order to fill the gap between the moveable floor and the stationary pool, either a movable boom or a trailing ramp must be installed. A moveable boom (or raise-able wall) is a partition that lifts out of the water and separates the movable floor section of the pool from the rest of the pool, providing both a physical and visual barrier between the deep water end of the pool and the elevated section.
Trailing ramps are installed to insure that there is no access under the pool floor when it is raised. The ramp is hinged to the moveable section of the floor and slides along the pool floor as the floor is being lifted.
So, while a moveable floor won't allow you to offer multiple water temperatures, it is a cost effective approach to make one pool all the various depths you may need.