Pre filter media?

[Higdonii]

Just a quick question.. I had a pond in the past that had been well established but the only filter I used was a skippys filter that I made and it had the sponges as media and I also put plants in it as well (hyacinth, iris, and pickeril rush).. This filter worked great for that pond, but with my new pond that was just built this year, this type of filter alone isn't getting the water as clear as I would like it to be, I added a bottom drain and pre filter as well and am wanting to know what would be the best media to put in my 55 gallon pre filter....... Should I use bio balls or a bunch of the little green sponges, or even polyfil or a mixture... Any help would be greatly appreciated.. Thanks

P.s. This pond is bigger than the last one and has a bio filter with waterfall that is considerably bigger than my last one as well