Hi all, is there a way to add a filter box to a Laguna Power Jet 600 (PT8200)

I have a two tier preformed pond. Its small but I don't know the capacity. I have a filter in the lower/smaller level, but it doesn't seem to keep the water clear. I thought adding another filter to the upper lever would help.

I already have a PT8200 still sitting in the box. Would just adding the pump to create more water flow help without a filter?