Its about 3700, about 4 foot deep plus 18 inches above the wall. We used to have a traditional 4 bay filter with a vortex but a garden re-design meant changing that to a nexus.
It was built in 2001 and took 4 skips. Some of the fish were in the smaller pond and are getting on to 15 years old, 3 of them are goldfish!
The inhabitants are friendly... and always hungry!
This was just after the few windy days, so the surface is a bit dirty.
Sorry if thi has gone a bit off topic, but the fish are carbon (based life forms!)