The bank of Bakki showers shown here are in the new fish house at Momotaro Koi, and it was built in 2003. It was being commissioned in the fall of 2003 with Koi from the autumn harvests. Note the large diameter green hoses which provide huge amounts of air to each pond. Each pond has a chamber built across one corner of it. This is where the bottom drains feed into, and where a large submersible pump takes the water up to the Bakki showers. The plumbing I recall was about 4” in diameter. The water is returned via a concrete shelf under the Bakki showers.