This is a true koi pond that I am currently building. Pond only will be roughly 10,800 gallons. It is 10x18x8. Filtration roughly 1000gallons extra which will include 2 4" aerated bottom drains each flow to their own settling chamber , these will then flow to 2 moving bed filters, which will then return via 5 returns in the bottom 2' of the pond. I have a remote skimmer that I use on formal ponds that will gravity flow to a nexus eazy pod then to a challenger 60 bead filter and then return via a sheer decent waterfall.2 3" midlevel drains will flow to pump then a custom made bakki shower/ trickle tower and will gravity flow to 5 upper level returns. Construction is concrete block walls, solid conrete floor and the liner system is polyurea.