Description:
A check valve is a small but critically important piece of equipment for any aquarium running an air pump. Without one, if your air pump loses power, water can siphon back through the airline tubing and into the pump, causing water damage or flooding. A check valve prevents this by allowing air to flow in one direction only, from the pump to the tank, while blocking any reverse flow of water.
This is particularly important if your air pump sits below the waterline of your tank, where the risk of backflow is highest. Even if your pump sits above the waterline, a check valve is inexpensive insurance against the unexpected, and something we recommend to every customer running an air pump.
These one-way non-return check valves from Pet Worx, an Australian company established in 1980, are simple to install. Cut your airline tubing and insert the valve in line between your air pump and your air stone or sponge filter, making sure the arrow on the valve points toward the tank. Compatible with standard 4mm airline tubing. Pack of 12, giving you enough for multiple tanks or setups across a fish room.
If you're running a Pet Worx Single or Twin Air Pump, or any other air pump pairing it with a check valve is strongly recommended.
Suitable for freshwater and marine aquariums.
Product Features:
- Prevents back-siphoning of water into your air pump during power loss or system failure
- One-way airflow design allows air to pass into the aquarium while blocking reverse water flow
- Helps protect air pumps from water damage and extends equipment lifespan
- Essential safety component for any aquarium running an air pump system
- Highly recommended for setups where the air pump sits below the aquarium waterline
- Simple inline installation between air pump and airline accessories
- Clear directional arrow ensures correct installation and reliable operation
- Compatible with standard 4mm aquarium airline tubing
- Ideal for multi-tank fish room setups and individual aquariums
- Suitable for freshwater and marine aquariums
Product Specifications:
- Type: Aquarium Air Check Valve (Non-Return Valve)
- Function: One-way airflow protection
- Compatibility: Standard 4mm Aquarium Airline Tubing
- Installation: Inline between air pump and air-driven equipment
- Brand: Pet Worx (Established 1980)
- Pack Size: 12 Pack
- Suitable For: Freshwater and Marine Aquariums
Items Included:
- 12 x Pet Worx Aquarium Non-Return Check Valves
Pet Worx - Check Valve - 12 Pack
Pet Worx - Check Valve - 12 Pack
Low stock: 4 left
Why Shop With Us — Our Guarantee & Shipping Info
Why Shop With Us — Our Guarantee & Shipping Info
✅ Quality Products - Reliable aquarium supplies for your setup.
🚚 $11.95 Flat-rate shipping - safe & reliable delivery, arrives within 2-8 business days.
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Tips Before You Buy — Product Guidance
Tips Before You Buy — Product Guidance
💡 Unsure which product is right for your tank? Visit our Education section or Blogs for help choosing the best equipment.
🐟 Beginners can start with: How to set up your aquarium, while everyone can check out Aquarium Maintenece & Care for ongoing tank tips!
🌿 Not all products are suitable for every tank size — Double-check dimensions and specifications before purchasing.
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We mention check valves in the descriptions of our air pumps and air stones for good reason. It's one of the cheapest accessories in the store and one of the most important. A flooded power board or a damaged air pump from a single power outage costs far more than a pack of check valves. The 12-pack makes it practical for fish room keepers and breeders running multiple air-driven setups.
Check valves are low maintenance but should be inspected periodically. If you notice reduced airflow from your air pump, a blocked or stuck check valve is a common cause. Replace if the valve no longer allows free airflow in the correct direction or shows signs of cracking or deterioration. With a 12-pack on hand, replacements are always ready when needed.
Frequently Asked Questions
What does a check valve actually do?
It allows air to flow in one direction only, from your air pump into the aquarium, and prevents water from flowing back down the airline. Without one, a power outage or pressure drop can cause water to siphon back into your pump, potentially damaging it or causing leaks.
Do I need one if my pump sits above the waterline?
Yes, it is still strongly recommended. Even when positioned above the waterline, unexpected power loss or pressure changes can still cause backflow. A check valve is cheap protection against expensive damage.
How do I install it?
Simply cut your airline tubing and insert the check valve inline between your air pump and your air stone or sponge filter. Make sure the arrow on the valve points toward the aquarium (direction of airflow). That’s all it takes.
How do I know if a check valve has failed?
If airflow drops significantly or stops, a stuck or blocked valve is often the cause. Remove the valve temporarily to test airflow. If performance returns, replace the valve. With a 12 pack, you will always have spares ready to go.
