Circulate Up to 70,000 Litres Per Hour in Very Large Ponds
The Aquascape Ext 18000 is a single-phase external pond pump rated at 18,400 GPH (69,638 LPH) with a maximum head height of 13.7 m (45 ft) and a 3,300-watt motor. It is the most powerful external pump in the Aquascape range for single-phase power sites, and it serves large koi pond and professional water feature installations that require continuous high-volume circulation beyond the capacity of submersible pumps.
High-Head, High-Volume External Pumping on Single-Phase Power
The Ext 18000's 13.7 m (45 ft) maximum head height is exceptional for a pump of its flow class, making it suitable not only for high-volume low-head installations but also for tall waterfall features and installations where significant pipe friction losses must be overcome. Single-phase operation means it can be used on any standard 115V or 230V residential or commercial power supply without requiring three-phase infrastructure.
| Specification | Value |
|---|---|
| Max Flow Rate | 18,400 GPH (69,638 LPH) |
| Max Head Height | 13.7 m (45 ft) |
| Power Consumption | 3,300 W |
| Motor | TEFC (oil-free, fan-cooled) |
| Voltage | 115 V or 230 V single-phase (field-selectable) |
| Inlet | 7.6 cm (3 in) |
| Discharge | 5 cm (2 in) |
| Installation | External (non-submersible) |
How to Use
Mount on a stable level surface below the pond water level. Connect the 3-inch inlet from the pond through a full-port valve and debris strainer. Connect the 2-inch discharge to the distribution system plumbing. Prime the pump before start-up. Connect to a suitably rated GFCI-protected outlet with correct gauge supply wiring for the amperage draw. For 230V operation, field-configure the motor per the motor nameplate and wiring diagram in the pump manual. Service the mechanical seal oil annually.
Ideal for very large koi ponds above 30,000 litres (8,000 gal), large professional pondless systems, commercial water feature installations, and waterfalls with significant head height requirements.

