Counter-current swimming
A counter-current system, also known as as jet stream system, operates on a closed circuit: water is drawn directly from the pool and returned to the pool, independently of the filtration system. It has no impact on the balance tank or the filtration pump sizing. Because usage is intermittent, the dedicated pump does not run continuously – it does not need to be factored into the ongoing hydraulic balance of the system.
The pump and jets must be integrated into the pool shell during construction. Retrofitting is possible on some configurations but always involves compromises on jet positioning and suction placement.
Waterfall
Two hydraulic configurations are possible. In the first, water is drawn from the pool and returned to the pool – a closed loop that has no impact on the balance tank volume or the filtration pump flow rate.
In the second, water is drawn from the balance tank. In this case, the waterfall pump adds to the total flow demand on the system, exactly as any other auxiliary pump would, and must be accounted for in the balance tank sizing and pump selection.
The choice between the two configurations depends on the desired effect and the hydraulic layout of the project. Both must be resolved at the design stage – the pipe connections cannot be added after the slab is poured.
In-floor cleaning system
An in-floor cleaning system replaces the conventional pool vacuum with a network of cleaning nozzles flush-mounted in the pool floor. Water is sent sequentially to each nozzle group via a multi-port valve in the plant room – the jets sweep the floor and suspend debris, which is then carried by the overflow current towards the channel and into the balance tank.
In an overflow pool, this system works in direct synergy with the hydraulic circuit: the continuous movement of water towards the overflow edge assists the cleaning process naturally. The system has no moving electrical components in the water, which gives it a significantly longer service life than a conventional automatic cleaner.
Movable floor
A movable floor allows the pool depth to be adjusted at the touch of a button – from full swimming depth to a shallow recreational level, or raised entirely to deck level to create a usable terrace surface. It is one of the most technically sophisticated options available for a private pool.
For an overflow pool, the movable floor must be designed in from the outset. The pool structure needs to be deeper than the intended swimming depth to accommodate the floor mechanism and its hydraulic drive system. The floor itself is typically constructed from a marine-grade stainless steel 316L frame, controlled by a water-hydraulic cylinder – which eliminates any risk of oil contamination of the pool water.
The visual result, when the floor is raised to deck level, is a seamless transition between the pool surround and the floor surface. For a high-end overflow pool project where the water line is already a design feature, a movable floor extends that precision to the entire pool envelope.
Retractable glass walls
For projects where the pool needs to be enclosed without compromising the visual effect of the overflow edge, retractable glass wall systems offer an architectural solution. Unlike traditional pool enclosures, which obstruct the view and break the continuity of the pool with its surroundings, retractable glass panels disappear entirely when open – preserving the infinity effect.
This option requires early coordination between the pool designer, the structural engineer and the glazing specialist. The track system and panel storage need to be integrated into the pool surround at the construction stage.
Finishes that define the result
Two finishing decisions that are often underestimated have a direct impact on the visual quality of the completed pool. The first is the choice of pool fittings – inlets, drains and vacuum sockets are available in stainless steel or in a colour matched to the pool lining. Visible fittings in a contrasting colour interrupt the continuity of the water surface; tone-on-tone or stainless steel fittings disappear into the finish.
The second is the lining itself. For an overflow pool where the water surface is the primary visual element, the lining colour and texture determine how light is reflected and how the water reads from outside the pool. These are design decisions with permanent consequences – they cannot be changed without a full pool renovation.
Morana's advice
The options listed here share one common requirement: they all need to be on the table at the brief stage. A counter-current pump specified after the shell is built will compromise on jet positioning. A movable floor added to an existing pool requires structural intervention. A waterfall connection to the balance tank that was not planned for will require the plant room to be redesigned.
The technical package we produce for each project integrates these choices into the hydraulic design from the outset – so that the finished pool performs exactly as intended.