Hi,
Being looking through this thread. Interesting points of discussion from everyone.
When koi keepers ask for assistance I see a common thread in this and other forums - everyone makes suggestions based on the configurations and equipment they are comfortable with and usually have themselves.
So the recommendations to koi keepers asking for advice almost always involve much extra expense. They are advised to add everything except the kitchen sink, change or dynamite out of their gardens their existing filtration systems.
The challenge, in my opinion, is to get koi keepers systems working with what they have or alternatively with the minimum amount of expense.
That’s when it becomes a challenge and interesting.
Regards,
Chris