Resun Undergravel Filter

Modular undergravel filter that uses the aquarium substrate as its filter medium for mechanical and biological filtration. Water passes through the layer of sand or gravel, keeping the substrate clean. The grid is made of 14 × 7 cm plates that clip together, also at right angles, so the filter can be fitted to the tank floor; surplus connectors can be cut off. Water movement is driven by an air pump (not included), with air fed into the riser tube through the supplied airline and air stone. The telescopic riser adjusts from 30 to 50 cm and its outlet turns through 360°.

• RS16: 16 plates, 54 × 30 cm, 1 riser, airline and air stone
• RS20: 20 plates, 70 × 30 cm, 1 riser, airline and air stone
• RS24: 24 plates, 84 × 30 cm, 2 risers, 2 airlines and air stones