20mm Metric Check Valve
SKU: PVC-CHKVLV-20
- Backflow Protection: Prevents back-siphoning and sump overflows by ensuring water only flows in one direction.
- Precision Metric Sizing: Designed for 20mm metric PVC pipe (approx. 0.75" OD), a standard for Reef Octopus internal plumbing.
- Industrial Durability: Constructed from high-quality grey UPVC for superior strength and a professional appearance.
- Saltwater Safe: 100% non-corrosive materials designed specifically for the harsh environment of marine reef systems.
- Reliable Sealing: Precision-engineered internal mechanism provides a secure seal even at low back-pressure.
- Ideal For: Skimmer recirculating loops; small return lines; dosing and reactor feed protection.
20mm Metric Check Valve
The 20mm Metric Check Valve (Non-Return Valve) is an essential safety component for precision aquarium plumbing. This valve is specifically sized for 20mm Metric PVC pipe, which is the primary diameter used for air-water mixing lines and recirculating assemblies on many Reef Octopus protein skimmers and high-end European-spec reactors.
By allowing water to flow in only one direction, this valve protects your system from the risks of back-siphoning during power outages or pump failures. In compact filtration setups, a 20mm check valve ensures that water remains within the reactor or skimmer body, preventing air-locks and ensuring an immediate restart when power is restored. Constructed from industrial-grade, saltwater-safe grey UPVC, it offers a much cleaner and more durable alternative to standard white residential plumbing.
Key Features
True Metric Calibration: Fits 20mm OD metric pipe—perfect for maintaining factory Reef Octopus and Maxspect equipment.
Compact Design: Ideal for tight plumbing runs inside skimmer bodies or under-cabinet sumps where space is limited.
Low Maintenance: Smooth internal walls reduce detritus buildup and organic scaling within the valve mechanism.
Chemically Inert: Made from high-grade PVC that will not leach harmful substances into sensitive reef environments.
Socket-Style Connection: Slip x Slip configuration for a permanent, high-strength solvent weld.
Ideal For
Reef Octopus Skimmer Repair: Replacing internal check valves in recirculating or venturi assemblies.
Small Manifolds: Protecting feed lines for calcium reactors, carbon reactors, or UV sterilizers.
Dosing Systems: Preventing high-concentration additives from back-flowing into reservoirs.
Images shown are representative of the product family. Materials, sizes, and configurations may vary.
What’s Included:
(1) 20mm Metric PVC Check Valve
Specifications:
Size: 20mm
Connection Type: Slip x Slip (Socket)
Material: High-grade Grey UPVC
Mechanism: Non-Return One-Way
Compatibility: 20mm Metric Pipe ONLY
- Locate the flow direction arrow on the valve body; ensure it points toward the aquarium/output.
- Cut the 20mm metric pipe square and remove all burrs with a deburring tool.
- Perform a dry-fit to ensure the valve is oriented correctly and is accessible for future inspection.
- Apply a thin layer of PVC primer and solvent cement to both the pipe end and the valve socket.
- Insert the pipe into the fitting and hold for 20–30 seconds.
Pro Tips:
For the most reliable seal, check valves are best installed in a vertical position where gravity assists the internal sealing mechanism.
Confirm Your Metric Size. A 20mm metric valve will not fit standard 1/2" or 3/4" USA pipe. 20mm is approximately 0.78 inches. Always measure your pipe with a caliper before ordering to ensure you are purchasing the correct metric component.
Not a Substitute for Sump Volume. While check valves are excellent for managing water levels, never rely on them as your only defense against a flood. Always ensure your sump has enough "empty" volume to handle a standard back-siphoning event in case the valve fails to seal perfectly due to debris or calcium buildup.
Keep it Accessible. Small check valves can occasionally trap debris or a wandering snail. Always install your 20mm check valve in a location where it can be easily reached for inspection or cleaning without dismantling the entire filtration system.