EHEIM Air Pump 100 with Diffuser

The EHEIM Air Pump 100 is a small air pump sold with a diffuser, so you have what you need to start bubbling air into a tank. Eheim lists it for aquariums up to about 30 gallons. It’s a simple, compact choice for a community tank, a hospital tank or a shrimp setup that needs a little extra oxygen.

What aeration does

An air pump doesn’t add oxygen directly through the bubbles so much as it moves the water. Rising bubbles break the surface and keep it moving, which speeds up gas exchange. That matters most in warm water, heavily stocked tanks and tanks with medication in them, since many treatments lower oxygen levels.

What’s in the box

• The Air Pump 100 itself, a compact black unit
• A diffuser that breaks the air into finer bubbles

You’ll want some airline tubing and, ideally, a check valve if your kit doesn’t include them.

Placement

Sit the pump on a stable surface above the waterline, or put a check valve in the line. Either way, water can’t run back into the pump if the power goes out. Put the diffuser near the bottom, where the bubbles will lift the most water as they rise, and away from the filter intake so bubbles don’t get pulled into the impeller.

Running a sponge filter

The pump can also drive a small sponge filter instead of the diffuser. That gives you gentle flow and biological filtration in one, which suits fry and shrimp tanks.

When to size up

For tanks larger than about 30 gallons, or for running several devices at once, choose a pump with more output and separate controls, such as the Tetra Whisper AP150. For a desk-size nano, the hygger quiet mini pump is a smaller option.