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Preguntas frecuentes sobre Pool shell material

What do pool shell fittings include?

Pool shell fittings are the components embedded directly in the structure to enable water filtration and lighting circuits.

This category includes essential technical components:

Surface skimmers for collecting leaves and floating particles.
Inlet and suction fittings for returning filtered water and connecting a pool vacuum.
Main drains for emptying and deep-water recirculation.
Wall conduits and lighting niches for housing watertight underwater lights.

Combining these components correctly determines the shell’s hydraulic balance and prevents dead zones in the filtration circuit.

I have a pool with a liner and need to replace the accessories. What differences should I check compared with a concrete pool?

The critical difference lies in the sealing and fastening system required for each type of lining.

Components for concrete pools with à carrelage are embedded directly in the shell using mortar and have no mechanical elements for external pressure. By contrast, accessories for shells with reinforced membrane or PVC liner require a body fitted with threaded metal inserts, front clamping flanges, and a double neoprene or EPDM seal. This mechanism presses the liner against the accessory opening, preventing water from escaping through the wall. If you install a component designed for a traditional concrete pool in a liner pool, water will inevitably leak around the opening as soon as you fill it for the first time.

How do you choose pool shell fittings based on the pump flow rate?

The pool shell fittings must be selected by calculating the number of hydraulic components required based on your filtration pump’s nominal flow rate.

Each component has a maximum water flow rate to prevent pressure losses or overpressure in the system:

Standard skimmer: handles between 5 m³/h and 7.5 m³/h per unit.
50 mm return nozzle: handles an approximate flow rate of 4.5 m³/h to 5 m³/h.
Main drain: size it to ensure the suction velocity does not exceed 0.5 m/s for safety.

For an installation with a 10 m³/h pump, you need at least two return nozzles and at least one wide-mouth skimmer or two standard openings to preserve the equipment’s service life.

I’m going to replace an old halogen light in the pool shell without doing any work on the niche. Which model is compatible?

To replace a traditional halogen light without altering the pool shell masonry, install a standard PAR56 lamp or an ultra-flat spotlight designed to mount directly onto existing niches.

For renovated pools, the recommended technical option is the White LED light without niche - Renovation by Weltico, designed to fit onto the existing outlet or niche without fully draining the pool or replacing the wall fittings. This type of lighting operates at low voltage (12 V) and reduces electricity consumption to below 30 W, compared with the usual 300 W of a classic incandescent light. Always check that the mounting diameter matches the existing ring before completing your purchase in our online store.

Which material is most resistant for fittings embedded in the pool shell?

High-impact ABS plastic with UV protection is the predominant and most well-balanced material for components embedded in private and communal swimming pools.

This thermoplastic polymer offers specific mechanical advantages:

Total immunity to oxidation caused by salt chlorination or conventional chlorinated products.
Structural flexibility to absorb slight stresses caused by ground settlement without cracking.
Additional AISI-316 stainless steel fasteners to prevent galvanic corrosion spots where the flanges are mounted.

Compared with metal options that require specific grounding against stray currents, treated ABS retains its color and mechanical properties for years without requiring structural maintenance.

I’ve found a crack in the skimmer of my above-ground pool with a steel wall. Can I replace just the nozzle and body, or do I need to replace the whole assembly?

For above-ground structures, it is essential to replace the complete assembly consisting of the skimmer, gasket, and return nozzle to restore a watertight seal on the metal cutout.

The Skimmer + AR100 return nozzle kit from Gre includes the outer housing, the swing flap, the strainer basket, and the double perimeter seal adapted to the steel wall. Installing components with different reference numbers often creates millimeter-sized gaps in the cutout, leading to water leaks that eventually corrode the pool’s outer wall. Replacing the complete unit ensures even tightening of the screws and extends the structural safety of the pool throughout the 2026 swimming season.

How do you check pipe compatibility when connecting to the pool structure?

Pipe compatibility with the pool structure depends on checking the type of connection, whether it is a male/female threaded connection in inches or a smooth solvent-weld connection in millimeters.

The hydraulic standards for these connections are strictly divided:

Metric solvent-weld connection: PVC pipes with an outside diameter of 50 mm or 63 mm, in a pressure rating.
Threaded connection: 1 1/2-inch (approximately 48 mm) or 2-inch (approximately 60 mm) gas-pitch threads located at the bottom of the skimmer or on the nozzle.

To achieve a leak-free connection, apply high-density Teflon tape to the plastic threads and PVC-specific adhesive to the smooth sections, allowing 24 hours to dry before pressurizing the pool.