How to Use Airline Accessories in Your Aquarium

How to Use Airline Accessories in Your Aquarium

5 min read

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. Then, why are there so many airline accessories and which ones do you actually need? Keep reading as we briefly explain five of the most common airline parts that can transform the way you use your air pump.

1. Check Valve

If you only get one item from this list, a check valve is an essential must-have. It contains a flapper or stopper that allows air to flow in one direction (into the tank) and stops water from flowing in the other direction (out of 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. In extreme cases, this can lead to an electrical fire if you have appliances or power strips sitting in the water.

Check valves are necessary for every aquarium device that uses airline tubing, whether it’s a sponge filter, aquarium ornament, brine shrimp hatchery, or carbon dioxide (CO2) injection system. (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.) For installation, simply cut the airline tubing between the device and air pump and connect the check valve in between. The end of the check valve with the flapper (which looks like a colored or horizontal bar) should be facing 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.

aquarium check valve

Connect the check valve between the air pump and air-driven device such that the horizontal or colored bar is facing the air 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 stops the water at the rim rather than near the air pump where the water pressure in the airline tubing could cause a leak. Also, make sure the airline tubing is cut straight and cleanly, free of any tears. Finally, check the airline tubing to make sure it hasn’t dried and hardened over time, which could cause the connection to loosen and drip during a power outage.

2. Air Valve

An air valve sounds similar to a check valve, but instead it is used to control the amount of air flow coming from your air pump into the aquarium. Some air pumps come with an adjustable knob that allows you to increase or decrease the air pressure, but if your air pump doesn’t have one and the bubbles are too strong, then this is the perfect tool for you.

To install an air valve, cut the airline tubing 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). Screw tight the knob to decrease flow and loosen the knob to increase flow. Even when the knob is tightened down all the way, a small amount of air usually still escapes through the air valve. This prevents too much back pressure from building up and potentially damaging your air pump.

aquarium air valve

An air valve controls the amount of air flow coming from your air pump into your air-driven 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. Also, make sure you make clean cuts in the airline tubing and check the connections periodically to make sure the air valve is still snuggly connected.

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. Another use case would be diverting air off your main aquarium to a second tank or a quarantine tub. Each pack comes with five T airline connectors, so you could theoretically chain multiple splitters together to create additional air streams.

T splitter for aquarium airline tubing

The T splitter divides the air flow coming from the green air pump, and then the air valve controls how much air reaches the sponge filter.

We highly recommend using air valves when splitting the air stream so that you can fine-tune how much air goes to each line. As usual, ensure that you use airline tubing with clean-cut ends and periodically inspect the connections to make sure they haven’t weakened over time.

4. Gang Valve

A more efficient accessory for splitting one air stream into multiple paths is a gang valve. The model we offer features four outlets and up to two inlets. The two inlets allow you to add one or two air pumps as desired and then split it up four ways. Alternatively, you can connect daisy-chain two gang valves together, giving you eight ways to split your air.

aquarium gang valve

A gang valve is a great way to split air between multiple aquariums or air-driven devices.

Keep in mind that each time you split the air, each outlet has a weaker output and less air going through it. The more outlets you have, the more adjustments need to be made on each air stream. Luckily, there’s no need to get any air valves because each outlet has its own adjustable switch to regulate how much air goes to each individual device.

5. Air Stone

An air stone is a small, weighted bubbler that produces very small bubbles in the water. This simple accessory helps to gradually diffuse air into the tank, improve oxygenation of water, and minimize the amount of bubbling noise you’ll hear. You can use an air stone by itself or in conjunction with a sponge filter to improve the efficiency of the filtration. 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).

air stone in a sponge filter

This diagram shows where an air stone goes inside a sponge filter to optimize its performance. To install an air stone inside a sponge filter, read 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.