You do want the extra biofiltration but not at the expense of adequate filter flow. It looks to me that the scrubbers are stuffed into the filter so tight that they are bending the main filter elements out of shape. I would try maybe cutting one into smaller pieces so that it goes in without distorting the main filter elements. I have cut some in half in my canister filter so that it would better fill a canister basket without slowing my flow much and it worked out great. The pieces of scrubber do not need to be neat but they do need to be pieces that will stay together or you will be cleaning individual plastic bits from all over the tank. If that filter is like my whisper series filter, significant flow restriction turns into flow that bypasses the filter completely and just leaks out next to the inlet tube.