My first DIY project.
Choice of media filter: my choice are ceramic rings
A plastic bottle
An airline tube
2 heater suction cups
A piece of thick sponge
Rinse the plastic bottle clean.
Rinse the ceramic rings.
Open the cap and fill it up with your choice of filter media.
Drill a few holes in the cap and a few holes at the bottom of the bottle.
Close the cap.
Drill two holes for the suction cups, one near the top, one near the bottom of the bottle.
Insert the suction cup's nub into the hole.
Drill a small hole near the cap that the airline tube can fit.
Put the airline into the hole above.
Cut the sponge into a small size you like and cut a thin opening enough to fit on the cap.
Place the sponge on the cap.
Place filter in the corner of the aquarium.
Connect the airline to the air pump
Turn on the air pump.