Supplying Koi & Pond Enthusiasts With Confidence
1-2 Day Delivery From £3.79

Free when you spend £49

All Products Sourced Within The UK

99% Are Manufactured In England

Expert Support & Help


Large Pond Bottom Drain and Aqua Jet Air Diffuser




9”x 4” Bottom Drain and Aqua-Jet Air Diffuser

This Bottom Drain has been designed to work in conjunction with 110mm solvent weld pipe (please view our pipe identification chart for finding your correct pipe size)

The 9″x 4″ Bottom Drain and Dome are designed to give a high-efficiency low maintenance system when constructing a pond, as it draws debris and solids from the pond floor. Using a gravity feed system is more beneficial as the solids get fed straight into your filter system for removal and not liquidized into fine particles as within a  pond pump, the finer the particles the harder it is for your filter system to remove them, resulting in a poorer quality of water. The 110mm outlet on the 9″ x 4″ Bottom Drain gives a high flow of water which gives a good “draw” removing debris from across the bottom of the pond

This design of Bottom drain features an aerated dome; the aerated dome has a coil of perforated hose that sits neatly on top. Not only does the aeration benefit your pond and your fish but it also helps with pulling debris into your sump making it more effective. (Explained at the bottom of the listing description)

The aerator on this dome is neatly coiled on the Bottom Drain dome and is over 5 meters in length, 5420mm to be exact. The Aqua-Jet range has been tried and tested across the globe and is considered the best money can buy simply because it offers superb aeration like no other design on the market.

The aerator is fitted with an air input tee that will accept flexible airlines with an internal diameter (ID) of 6mm. This kit comes supplied with 10 meters of flexible clear PVC airline (6mmID-8mmOD)

Replacement Parts

This model of Aqua-Jet aerator allows for the perforated hose to be replaced, extending the longevity of the products lifetime. The perforated hose simply unclips and is replaced with a new one from the replacement kit. (For more information please see our product archive)

Installing to an Air pump

We recommend the use of an air pump between 60-80 LMP for sufficient performance.
Simply connect the airline that is attached to the Bottom Drain to your air pump. For ease of assembly place the tip of the airline in warm water for a few seconds and push onto the chosen fitting.

Where to locate my bottom drain?   

Bottom drains are located on the pond floor and should be positioned in the deeper areas of the pond. Bottom drains consist of a sump, which is set into the pond’s base and is attached to the pipe-work.

A pond can be built with multiple bottom drains along the floor, leaving no areas in the pond for sludge to accumulate.

Planning and Construction                                                                                            

As the pipe-work used in the construction of a gravity-fed filter runs under the pond and is usually set in concrete, bottom drains should be considered at the outset of pond planning and installed as the pond is constructed. Bottom drain setups are much more efficient than having a pump situated in the pond, feeding a filter. Bottom drains can handle larger solids than most types of pond pumps, and are far less likely to block or become hampered by debris.

The sump is supplied with a flange ring, which can be screwed to its top lip. If the pond is liner-based, the liner should be sandwiched between the flange ring and the sump lip, and adhered with a non-toxic sealant, creating a water-tight seal. If the pond is constructed from concrete the flange ring is not required. The top of the sump should be set level with the pond’s final rendered layer. A gap of usually around 2 to 5cm is set between the top of the sump and the dome, and should stop smaller pond fish from entering the filter system.

To obtain a maximum flow-rate and reduce the build-up of debris in the pipe-work connecting the bottom drain to the filter, the pipes should run as directly as possible, and any bends should have a large curved radius.

My existing pond doesn’t have a Bottom Drain installed                     

 If you have an existing pond that doesn’t have a bottom drain installed and you don’t want to undertake the huge task of completely rebuilding your pond from the ground up, don’t worry. eco-filtration has the answer.

eco-filtration stock the largest range of Weighted Suction Domes available for the koi market. A Weighted Suction Dome is a portable bottom drain. Offering the same great advantages as a Bottom Drain sump but without having to rebuild your pond. For more information on the Weighted Suction Dome range please see our product archive.

Bottom Drains Solvent Weld Sump                                                                            

The sump is manufactured with a joining socket that has a 110mm internal diameter (ID) this will receive waste pipe with an outside diameter (OD) of 110mm (please refer to the pipe dimension and identification chart)

Pressure or Waste Solvent Weld Pipe?                                                                         

If the application of 4” pressure pipe(114.3mm) is needed eco-filtration stock a large range of reducing/joining bushes. We sell a 110mm – 114.3mm reducing socket purposely designed for the job. Converting your standard 4” waste (110mm) Bottom Drain Sump socket to receive 4” pressure pipe (114.3mm) (please see our product archive for further details)

Supplied- 9″ x 4″ Bottom Drain Sump, Aqua-Jet Aerated Dome, Ring, High Adjuster Tube, 12 x Stainless Steel Screws,10 meters of Flexible Clear PVC Airline (6mmID-8mmOD) Instruction Leaflet

 Have You Seen The Replacement Domes?

Also available to purchase separately are the aerated Bottom Drain domes. Upgrade your Bottom Drain dome to an aerated version at a later date. There are 3 different models in the aerated bottom drain range

  • Single ring Aerator Dome
  • Aqua-Jet Air Diffuser Aerated Dome
  • Rubber membrane Aerated Dome

 Why An Aerated Bottom Drain? 

The benefit of having an Aerator on your Bottom Drain is the rising air bubbles make an uplift, this circulates the water towards the Bottom Drain making the Bottom Drain up to 30% more efficient at removing debris and waste from the pond. Not only does it help with the performance of the bottom drain but also aerates the water making for a healthier environment in your pond.

For more information please view our product archive

Additional information

Weight 3.394 kg