Bakki showers are a type of trickle filtration.

First developed by the Momotaro Japanese koi farm, the bakki shower attempts to simulate natures way of filtering water. Similar to a mountain stream where water cascades over rocks.

Biofilms and algae grow on the rocks and feed on the nutrients in the stream, essentially filtering the water. In the case of the Bakki shower, ceramic is placed in trays and the water pumped to the top of the filter and trickles through the media, eventually flowing back to the pond.

Momotaro Koi Farms developed the bakki shower with stainless steel trays. Since that time many "DIY bakki showers" have been designed with variations on them. Plastic and fiberglass boxes or crates have been used with success.

In all its simplicity there is a lot of higher chemistry going on between the bio film and the water column. The biochemistry is better explained in this book : Biology of the nitrogen cycle By Hermann Bothe, Stuart John Ferguson, William Edward Newton^[1]

The advantages of this type of filtration are:

Conversion of nitrogenous wastes

Off gassing of CO₂ maintains pH

Oxygen is reintroduced

This method of off-gassing and aeration is used widely in aquaculture.^[2]

The choices of Filter media vary greatly. Each filter media has different properties and therefore different performance. Here are some photos of different types:

• 
  Bacteria House

• Aquaculture Network Information
• Biology of the nitrogen cycle By Hermann Bothe, Stuart John Ferguson, William Edward Newton

v t e Ponds, pools, and puddles
Ponds	Ash pond Balancing lake Ballast pond Beel Cooling pond Detention pond Dew pond Evaporation pond Facultative lagoon Garden pond Ice pond Immersion pond Infiltration basin Kettle pond Log pond Melt pond Mill pond Polishing pond Raceway pond Retention pond Sag pond Salt evaporation pond Sediment pond Settling pond Solar pond Stepwell Stew pond Tailings Tarn Waste pond Waste stabilization pond
Pools	Anchialine pool Brine pool Infinity pool Natural pool Ocean pool Plunge pool Reflecting pool Spent fuel pool Stream pool Swimming pool Tide pool Vernal pool
Puddles	Bird bath Coffee ring effect Puddle Puddles on a surface Seep puddle
Biome	Beaver dam Duck pond Fish pond Goldfish pond Koi pond
Ecosystems	Aquatic ecosystem Freshwater ecosystem Lake ecosystem
Related	Aerated lagoon Bakki shower Big fish–little pond Body of water Constructed wetland Full pond Hydric soil Phytotelma Pond of Abundance Pond liner Ponding Puddle (M C Escher) Spring Swimming hole Water aeration Water garden Water Lilies (Monet) Well