Oase BioSmart 18000 Pond Filter

Oase BioSmart 18000 Pond Filter

High Capacity Flow Through Filtration for Medium Garden Ponds

The Oase BioSmart 18000 is a high performance flow through pond filter designed for medium sized garden ponds, goldfish ponds and lightly stocked koi ponds. Unlike pressurised filters, the BioSmart range operates as a gravity return box filter. As a result, it supports higher flow rates and provides generous biological capacity for long term water stability.

This filter delivers both mechanical and biological filtration within one durable housing. Layered coarse, medium and fine filter foams trap debris while simultaneously offering an ideal surface area for beneficial bacteria. These bacteria break down ammonia and nitrite, helping maintain balanced and healthy pond water.

The Oase BioSmart 18000 is suitable for:

• Up to 18000 litres without fish
• Up to 9000 litres with goldfish
• Up to 4500 litres with koi

Therefore, it is an excellent choice for medium capacity systems that require reliable and easy to manage filtration.

Intelligent Monitoring and Simple Maintenance

The Oase BioSmart 18000 includes an integrated pollution level indicator. This visual display clearly shows when cleaning is required, allowing you to maintain peak performance without guesswork.

Maintenance is straightforward. The in situ foam cleaning system allows you to compress the filter sponges using external handles. Consequently, trapped waste is released without removing the foams from the housing. This makes cleaning faster, cleaner and far less messy.

In addition, a bottom sludge drain with slide valve allows coarse debris to be discharged quickly. The built in thermometer provides instant visibility of pond water temperature, which is particularly useful during seasonal transitions.

For improved biological efficiency, the BioSmart 18000 can be paired with the Oase OxyTex pond aerator. When installed, OxyTex can increase biological filtration performance by up to 25 percent by improving oxygen supply within the filter chamber.

How the BioSmart 18000 Works and Set Options

Water enters the Oase BioSmart 18000 through a pump fed inlet and then flows through multiple filtration stages:

• Green coarse foam captures larger debris and solids
• Blue medium foams provide mechanical filtration and biological surface area
• Red fine foam polishes water and supports nitrification

As water passes through these layers, beneficial bacteria convert harmful waste compounds into less toxic substances. Once filtered, water exits via gravity return through the DN 75 outlet back into the pond.

Because this is a gravity return filter, it must be positioned above pond water level to allow water to flow back naturally.

The BioSmart 18000 is available as a standalone flow through filter if you already have a correctly sized pond pump. However, it is also available as a complete Oase BioSmart 18000 Filtration Set, which includes a fully matched pump, UV clarifier and hose for a balanced and ready to install system. The set version includes:

• Oase AquaMax Eco Classic 5500 pump
• Oase Vitronic 18W UV clarifier
• Oase Flexible hose

The set version provides a fully matched pump and UV system. Therefore, it is ideal for new pond installations or complete filtration upgrades where you want a properly balanced system from day one.

Key Features

• Flow through gravity return pond filter
• Mechanical and biological multi stage filtration
• 4 filter foams including coarse, medium and fine
• Integrated pollution level indicator
• Built in thermometer
• In situ foam cleaning handles
• Sludge drain with slide valve
• Compatible with OxyTex aeration system
• Can be partially buried up to one third of its height
• Durable UV resistant housing

Technical Specifications

• Maximum pond size 18000 litres no fish
• Maximum pond size 9000 litres goldfish
• Maximum pond size 4500 litres koi
• Maximum flow rate 5500 litres per hour
• Dimensions 382 x 555 x 408mm
• Filter foams 2 blue medium, 1 red fine, 1 green coarse
• Inlet sizes 25mm, 32mm, 38mm
• Outlet DN 75
• Sludge discharge DN 50

Technical information

• Match the pump flow to the filter and pond volume, allowing for head height and pipework losses.
• Keep unions, valves and waste outlets accessible for cleaning and maintenance.
• Use suitable hose, pressure pipe or DN discharge pipework where specified by the manufacturer.
• Check compatible UV bulbs, quartz sleeves, media and spare parts before the pond season starts.

Plan this product as part of the complete filtration layout, rather than as an isolated item. Check the recommended flow rate, inlet and outlet sizes, waste connection, access for cleaning and the space needed for routine servicing before installation. A well matched filter system is easier to maintain and gives more reliable water clarity over the long term.

Filter setup notes

Compatible Oase Discharge Pipework

This Oase product uses DN-sized outlet or sludge-discharge connections, so it is worth planning the pipework before installation. Use the matching DN pipework for the connection size stated on the exact filter or module, and avoid reducing gravity outlets unless the system has been designed for it.

• Oase DN50 Filter Discharge Pipework
• Oase DN75 Filter Discharge Pipework

Helpful links and compatible products

Use these links to plan the rest of the system around this product. The right pump, pipework, UV, media or spares will make the installation easier to set up, maintain and service.

• View the full Oase range
• Pond filters
• Pond pumps
• UV clarifiers
• Standard flexible pond hose
• Heavy duty flexible pond hose

More useful ranges and guides

These related ranges and guides may help you compare options, choose the right accessories and plan the full pond system rather than viewing this product in isolation.

• Browse pond and garden lighting
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