how to clean a slow filter?

[battered]

I have a Topfin 10 filter for my 10 gallon (unfortunately...but I didn't really know which brands were any good when I bought it). It's gotten to the point where the water that comes out from the filter kind of slides off to the side, not forming any bubbles or anything. Is there any way to clean this/fix the water flow? I know bettas like slower moving water, but it's gotten a little too slow in my opinion. I took out the biobag to see if that was the problem, but it seemed to run the same without it. I've cleaned the intake tube by running water through it, but it didn't seem to fix the problem either. Suggestions?