This project looks amazing, looking forward to updates :spop:
Are you able to source some riparian plants for this pond? It would add another dimension both aesthetically and functionally.
Your lighting is low-medium. I run 1x T8 tube on a similar sized tank and it grow most plants quite slowly. You could grow most stems under those lights.
I'm running a 1000lph internal filter on a 54L tank. Using a short spray bar it absolutely smashed it so I drilled the holes as big as possible and now the flow isn't as strong. Have a play around with different filter outlets and their placement in the tank.
Ten times turn over is good, the only issue you might have is with flow/current. Fish don't mind their water being filtered ten times an hour, they do however mind being blown around the tank.