Can any Filter be turned into a Bio Filter

I installed a pond a few years ago, installed by an acquarium shop.
The problem is that it used a typical acquariam filter. It never
really keeps the water clear even thoug i have a UV steralizer and a
fair amt of pond plants. My question- Can I simply buy bio balls or
other bio material and put it in my filter to creaet my own bio
filter?? this filter has the intake at the bottom of the drum and then
the water flows to the top where it exits to the pond?

It originallyc came with some large filter.. that ultimately got so
dirty and cracked that i replaced it with "horse hair" (you know,
those square fibrous spong like pieces that they cellat the pond
store_)..

will that work? can i just add bacteria to it...

or do i just scrap this and buy a real bio filter?

thanks!! it has been a bad week for ponds for me!