The Wetland is the main filter for the pond. The Wetland is filled with filtration pebbles and plants. This becomes a ECO system in time. Within days you will notice Dragonflies, Damselflies and other insects exploring the wetland. Over time frogs and even crabs will inhabit the Wetland. Section 2 is the Pond area where the Koi and other fish are located. The Wetland fills up with water via the pump and filters the water. The water overflows into the Pond before being sucked back to the pump. The debris settles at the lowest point of the Wetland and needs to be flushed out every 6-12 months. When sections of the plant life die off during the winter months, the debris rot and dissolve into the Wetland to become food for the plants. This is a natural cycle. Algae will grow in the Pond and Wetland. Algae are a plant and needs to be controlled in the system. If you remove the Koi and other fish from the pond you have a Natural Swimming Pool. It is a selling feature to have a Natural Swimming Pool or Wetland/Pond.