EPDM Rubber Membrane Air Diffuser, 4" with 1/4"-3/8" Barbed Inlet

The EasyPro RAD04-HB is a 4" (10 cm) EPDM rubber membrane air diffuser with a multi-size barbed inlet fitting accepting 1/4" to 3/8" airline tubing. Designed for pond aeration and water circulation, it produces a fine curtain of bubbles that improves dissolved oxygen levels and creates water movement throughout the pond column.

More Circulation Than Air Stones, Easy to Clean

EPDM rubber membrane diffusers produce slightly larger bubbles than traditional air stones, which translates to greater water movement and circulation rather than maximum oxygen transfer per bubble. For koi ponds and water gardens, this is the preferred trade-off: improved circulation and surface agitation keep oxygen levels healthy and reduce stagnant zones where algae and anaerobic bacteria can establish. Unlike air stones, rubber membrane diffusers are easy to clean by simply wiping the membrane surface. The multi-barb inlet cuts to fit either 1/4" or 3/8" airline tubing with no adapter required.

How to Install

Cut the barbed inlet to fit your airline tubing size (1/4" or 3/8"). Push airline tubing firmly over the barb and secure with a zip tie if needed. Place the diffuser at the pond bottom or desired depth, connect the airline to an air pump or compressor, and adjust airflow to the recommended 0.2 CFM for optimal bubble distribution. Clean periodically by wiping the EPDM membrane surface with a soft cloth.

Ideal for koi pond aeration, water garden circulation, and destratification applications where easy cleaning and durable rubber construction are preferred over fragile air stones.