It's funny you mention those - they were spotless! Literally, just wet!
For the first sponge in the filter they were too clean considering the rest of the fine sponges were so thick with sludge. This is why I think there is a lot of bypass happening - The second reason I'm considering another brand.
I don't mean to argue with you since your the guy on the sponge end of this conversation but I found with the tall sponges you have to soak them with water then hold by one end and swing/slap them against the side of the sink or bucket... a laundry sink helps here. Squeezing them got some gunk out but really didn't seem to get them clean for me.
Based on the colors in your photo they look like they have lots of embedded crud, mine looked like that and when I did the soak and swing routine there was gunk coming out of them for 10 minutes before I decided to swap them out for new ones. After new sponges my flow was restored, IMO it's worth a try, new sponges only set me back about $8 even at inflated Canadian prices.