Koi Pond Filtration - Problems

https://www.youtube.com/watch?v=7z4Cg3QOAb0

My koi pond filtration was never properly set up correctly (in my opinion). The algae in the koi pond is out of control. There are also a few other problems that make me want to dismantle the pond entirely. What to do? What to do? In this video, I explain my issues and dilemmas with my current koi pond and lay out a plan to fix it.
To be continued...