Ed this pond has a pretty basic filter system - single 6'' bottom drain with air dome, feeding a sieve & bead filter via 165w uv - single skimmer with dedicated pump & sieve & returned to a 7 ton gravel filter bed with full back flush facility.
2 x additional circulating pumps.
Total gallonage approx 8500 gal - flow rate approx 12000 gals an hours with all pumps running.
The bottom drain also has a direct flushing with auto daily water change, via a high flow chlorine exchange filter.
stocking is low with only 6 koi.