Aqua Medic Non Return Valve 4/6mm (2 pcs)
Pack size
2 valves
Water type
Freshwater + Marine/reef
Fits
4/6 mm airline tube, 4/6 mm CO2 tube, 4/6 mm dosing tube
Aqua Medic Non Return Valve 4/6mm (2 pcs)
Stops backflow before it reaches your air pump or doser. The Aqua Medic Non Return Valve 4/6mm (2 pcs) is a one-way check valve for 4/6 mm airline and dosing tube, fitted between a pump or doser and the tank so water cannot siphon back and flood the pump when it switches off. Sold as a pack of two, it is rated for air, CO2 and water lines alike.
Key features
- One-way flow — passes air, CO2 or dosed liquid in one direction only, and blocks it coming back.
- Fits standard 4/6 mm tube — the size used on most hobby air pumps, CO2 regulators and dosing pump outlets.
- Rated for air, CO2 and water — one valve style covers airlines, CO2 lines and dosing lines.
- Sold in pairs — enough from one pack to protect two separate lines, such as a doser and an airline.
- Compact blister-packed fitting — inline, no power or plumbing changes needed beyond cutting into the existing tube.
Specifications
| Spec | Value |
|---|---|
| Tube size | 4/6 mm |
| Rated for | Air, CO2, water |
| Pack size | 2 valves |
| Type | One-way check valve |
| SKU | AM41043 |
Suitable for, and not suitable for
Suitable for protecting air pumps, CO2 solenoids and dosing pumps from backflow and back-siphoning on 4/6 mm tube.
Not a substitute for a proper anti-siphon loop on gravity-fed top-off lines, and not sized for larger-bore return-pump or filter hose — check your tube diameter is 4/6 mm before ordering.
Care and maintenance
Check periodically that the valve still moves freely. Mineral build-up from dosed additives, such as calcium or alkalinity solutions, can occasionally stiffen the internal flap over time. Replace the valve if flow becomes restricted or it stops sealing.
Warranty and delivery
Covered by your rights under Australian Consumer Law. Standard delivery applies.
Common questions
Will this fit my CO2 regulator's tubing?
Yes, as long as your line is standard 4/6 mm tube — the size used on the great majority of hobby CO2 and air setups.
Does it stop my dosing pump siphoning into the tank when it is off?
Yes. That is its main job on a dosing line, along with protecting the pump head from backflow.
Can I use it on my return pump plumbing?
It is sized for 4/6 mm airline and small-bore dosing tube, not the larger hose used on return pumps — check your hose diameter before ordering.
Which way does it need to face?
Check valves of this type only pass flow in one direction. Fit it with the pump or doser on the inlet side and the tank on the outlet side, following any flow-direction marking moulded into the valve body.
