That is probably not why your filter is getting clogged but you need the black foam for you bacteria. Those filter bags are just really sucky. They grow slimy stuff very easily. I threw mine away and got a sheet of filter padding and cut my own. I just cut a strip as wide as the plastic thing, folded it over it, secured it with the clip and put it in the filter. Works better. You also need to twist the bottom of the filter off and clean the impeller. That is where the slime starts. It tells you how to do that in the instructions. Or here is a you tube video that shows how.
Cleaning whisper 2-10i internal power filter - YouTube
Once you get rid of what is in the impeller housing and replace the filter you should be good.