Air Manifold 18mm Inlet to 4mm, 8mm, 10mm, 12mm or 14mm 4 Way
4 way air manifold with adjustable ball valves for pond aeration systems
The Air Manifold 18mm Inlet to 4mm, 8mm, 10mm, 12mm or 14mm 4 Way is a practical air distribution fitting designed to split airflow from 1 pond air pump into 4 separate airline runs. It is ideal for pond aeration systems where you need to operate multiple air stones, diffusers, aerated filter chambers or airline feeds from a single air source.
Each manifold has an 18mm inlet, making it easy to connect to many pond air pumps using a suitable flexible rubber boot. The outlet tails then change depending on the option selected, allowing you to choose between 4mm, 8mm, 10mm, 12mm or 14mm tails to suit the airline being used.
Each of the 4 outlets also features its own ball valve, allowing the airflow to each airline to be individually adjusted. This is especially useful when balancing air between several different diffusers, air stones or filter chambers. For example, some airline runs may be longer than others, or certain diffusers may sit deeper in the pond, which can naturally affect how much air they receive. The built in valves allow you to fine tune each outlet so the system performs as required.
This makes the manifold much easier to use within larger or more detailed aeration setups. The larger 18mm inlet provides a straightforward connection from the air pump, while the 4 smaller outlet tails allow the air to be distributed to the correct airline size. The adjustable valves then give you control over how the air is shared between each outlet.
The 4mm outlet option is suited to smaller airline, compact air stones, aquariums, quarantine tanks and light duty aeration systems. The 8mm outlet option is suitable for standard pond airline, pond air stones, diffuser discs and many koi pond aeration setups. The 10mm outlet option is designed for larger airline, heavier duty sinking airline, larger diffusers and higher airflow pond systems.
Good aeration is important for fish health, biological filtration and overall water quality. Koi, pond fish and beneficial filter bacteria all rely on dissolved oxygen, especially during warmer weather when oxygen levels can fall. By splitting airflow between 4 separate outlets, this manifold allows a single air pump to supply several areas of the pond or filtration system at the same time.
It can be used with standard pond airline, weighted sinking airline, air stones, ceramic diffusers, moving bed filters and aerated biological chambers. For a neat underwater installation, it can be paired with Air Aqua Standard Sinking Airline or Evolution Aqua Premium Heavy Duty Sinking Airline, depending on the airline size and strength required.
Key benefits
- Splits airflow from 1 air pump into 4 outlets
- 18mm inlet for easy connection using a suitable rubber boot
- Selectable outlet tails in 4mm, 8mm, 10mm, 12mm or 14mm
- Each outlet has its own ball valve
- Allows airflow to be controlled and balanced
- Suitable for pond air pumps, air stones and diffusers
- Helps run 4 aeration points from 1 air source
- Useful for koi ponds, fish ponds and aquariums
- Suitable for aerated filters and quarantine systems
- Ideal for larger or more detailed aeration layouts
- Simple to install
- Ideal for new installations, upgrades and repairs
Reasons to buy
This 4 way air manifold is a useful fitting when you want to split air from a single pump into multiple airline runs. It gives you more control over where air is delivered and allows 1 air pump to operate up to 4 separate aeration points.
The adjustable ball valves make it easier to balance airflow between the 4 outlets. This is useful if you want some diffusers to receive more air than others, if the airline runs are different lengths, or if the diffusers are positioned at different depths.
It is particularly useful if you want to place air stones in several areas of a pond, run multiple diffuser discs, supply air to both a pond and filter system, or improve an existing aeration layout without adding another air pump.
The 18mm inlet also makes the pump connection simple when used with a suitable flexible rubber boot, while the outlet tail options allow you to select the correct size for your airline.
Choosing the correct size
The inlet side of the manifold remains the same across all 3 options.
Inlet size: 18mm
Connection type: Suitable for connection to many pond air pumps using a flexible rubber boot
The size selected refers to the 4 outlet tails.
4mm outlet tails
Suitable for smaller airline, aquarium air systems, compact air stones, quarantine tanks and light duty aeration setups.
8mm outlet tails
Suitable for standard pond airline, pond air stones, diffuser discs, koi pond aeration systems and aerated biological filters.
10mm outlet tails
Suitable for larger airline, heavy duty sinking airline, larger diffusers, higher airflow systems and more demanding pond aeration installations.
Always choose the manifold outlet size to match the airline you plan to use. You should also check the air pump connection, airline size and diffuser connection before ordering.
Suitable applications
- Koi pond aeration
- Garden pond aeration
- Fish ponds
- Quarantine tanks
- Aquarium air systems
- Pond air stones
- Ceramic air diffusers
- Aerated biological filters
- Moving bed filters
- Pond oxygenation systems
- Aquaculture systems
- Pond maintenance and repairs
- Professional pond installations
- Multiple diffuser installations
- Larger pond aeration layouts
Product specifications
- Product type: 4 way air manifold
- Inlet size: 18mm
- Inlet connection: Suitable for use with a flexible rubber boot
- Outlet options: 4mm, 8mm, 10mm, 12mm or 14mm
- Outlet quantity: 4 outlet tails
- Flow control: Individual ball valve on each outlet
- Application: Splitting and controlling airflow from 1 air pump into 4 airline runs
- Suitable for: Pond air pumps, airline, air stones, diffusers and aerated filters
- Installation type: Inline air distribution fitting
Installation guidance
Select the correct outlet size to match the airline being used.
Connect the 18mm inlet to the air pump using a suitable flexible rubber boot.
Push the airline securely onto each outlet tail.
Use the ball valves to adjust and balance airflow between the 4 outlets.
Check all connections are firm before leaving the air pump running.
Position the manifold where it can be accessed for future inspection or adjustment.
Use suitable airline clips where required for a more secure connection.
Using larger airline with this manifold
The 12mm and 14mm outlet options are useful on larger pond and lake aeration systems where a bigger airline or trunk line is being split into separate diffuser runs. For very heavy underwater runs, compare this manifold with our Super Heavy Duty Weighted Airline, which has a 1/2 inch internal diameter and is supplied in 30 metre lengths. Always check the airline diameter, barb size and clamp arrangement before installation.
Related 8mm outlet manifold
For systems that need one larger inlet feeding four 8mm outlet lines, see the 4 Way Air Manifold with 8mm to 14mm Inlet and 8mm Outlets. It is useful when a main 8mm, 10mm, 12mm or 14mm air feed needs to be split neatly to four 8mm diffuser or airline runs.
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