I revived it recently and changed the tanks used inside. Upgraded the 4"x4"x4" tanks to 4"x6"x8". Here is the link
top view
pump & sponge filter
pipe
drip to tank
Basically, this is how it works:
1. Pump brings water up the PVC pipe then distributed to the tanks with the air hose
2. Water overflows from the tanks and flows to the catch basin (bigger tank)
3. Water in the catch basin is filtered by the sponge as it is sucked in again by the pump
