How to use Airline Accessories in Your Aquarium

How to Use Airline Accessories in Your Aquarium

Aquarium air pumps are quite easy to use – just connect the pump to the air-driven device (like a sponge filter) using some airline tubing and plug it in. So why is there so many accessories for airlines? And which ones are you really going to use? Keep reading as we briefly explain five of the most common airline parts that can transform the way you use your air pump.


1. Verify Valve

Check valves are essential if you have to get just one item from the above list. This valve contains a flapper, or stopper. It allows air to flow in one direction (into your tank) and prevents water from flowing in another direction (outside the tank). This cheap but important accessory prevents water from siphoning out of your aquarium if the air pump turns off or stops running during a power outage. Water leakage out of the airline tubing usually results in damage to your air pump, as well as flooding all over your floor. This can result in an electrical fire if there are power strips or appliances that have been sitting in the water.

For any aquarium device that utilizes airline tubing, such as a sponge filter, ornament, brine shrimp hatchery or carbon dioxide (CO2) injection, check valves are required. (The only case where a check valve is not needed is if the air pump or CO2 tank is located higher than the rim of the aquarium.) Simply cut the airline tubing that runs between the device & air pump, and then connect the check valve between them. The check valve’s flapper (which is a horizontal or colored strip) should be facing towards the air pump. If you install the check valve backwards, no air will flow when you turn on the air pump, so just flip the check valve around.

Connect the check-valve between the air pump & air-driven device so that the horizontal bar or colored bar faces towards the pump.

The best practice is to place the check valve outside the aquarium (not in the water), close to the top of the fish tank. This position prevents water from getting to the rim and not near the air pump. The water pressure could cause leakage if it is too close to the tube. Make sure that the airline tubing has not been twisted or damaged. Final, make sure to inspect the airline tubing for any signs of dryness or hardening. This could lead to the connection leaking during an outage.

2. Air Valve

Although it sounds like a check valve an air valve is actually used to regulate the airflow from the aquarium’s air pump. An adjustable knob is available on some air pumps to allow you to increase or decrease air pressure. If your pump does not have this feature and the bubbles seem too strong, then this tool will be perfect for you.

Install an air valve by cutting the airline tube between the air pump, and the air-driven device. Then connect the recently cut ends of the airline tubing to each end of the air valve (direction doesn’t matter). To decrease flow, tighten the knob and then loosen it to increase flow. The air valve usually allows a little air to escape even when the knob has been tightened completely. This keeps back pressure from building up, which could potentially damage your air pump.

An air valve regulates the airflow from your pump to your aquarium device.

As with the check valve, we recommend that you add the air valve near the rim of your fish tank for easy access. Make sure to cut the airline tubing cleanly and make sure that the connections are checked regularly to ensure that the air valve is connected properly.

3. T Splitter

The tee airline splitter gets its name from its T shape that splits one stream of air into two paths. This functionality is useful if you only have one air pump but wish to run a second air stone or aquarium decoration in the fish tank. You could also use this feature to divert air from your main aquarium into a second tank, or quarantine tub. Each pack comes with five T airline connectors, so you could theoretically chain multiple splitters together to create additional air streams.

The air flow from the green air pump is divided by the T splitter, and the air valve regulates how much air gets to the sponge filter.

Air valves are highly recommended for splitting the air stream. This allows you to fine-tune how much air is going to each line. You should use clean-cut ends on airline tubing and inspect them regularly to ensure they aren’t damaged.

4. Gang Valve

A more efficient accessory for splitting one air stream into multiple paths is a gang valve. This model has four outlets and two inlets. You can add as many or as few air pumps you like and split the air up to four times with the two inlets. You can also connect two daisy-chain gang valves together to give you eight ways of splitting your air.

A gang valve can be used to divide air between multiple air-driven devices or aquariums.

Remember that every time you split the air, each outlet produces a lower output and allows less air to pass through it. You will need to adjust each air stream for every outlet you have. You don’t need any additional air valves, as each outlet has its very own adjustable switch to control how much air goes to it.

5. Air Stone

An air stone is a small, weighted bubbler that produces very small bubbles in the water. This accessory is a simple way to diffuse air into your tank, increase oxygenation, and reduce the bubbling sound you hear. An air stone can be used alone or in combination with a sponge filtrate to increase the efficiency of the filter. The air stone creates a steady stream of tiny bubbles (instead of large, intermittent bubbles) that produces constant lift in the sponge filter – much like a continuously running escalator (versus an elevator that starts and stops all the time).

This diagram illustrates where an airstone goes in a sponge filtre to maximize its performance. For more information on how to install an Air Stone inside a sponge Filter, please refer to our sponge Filter Installation Guide.

Running an air-driven device like an aquarium filter, air stone, or bubbler is one of the easiest ways to increase surface agitation and oxygenation in your fish tank. For more details on how to set up a fish tank air pump (and make it quieter), read our full installation guide here.