I used to use Classic 150 and Experience 150. Two different models the same problem, not good filtration, never! They have a sponges with large pores which does not make a filtration. water passes freely through the sponge, all dirty items too! Everything my aquarium water was dirty, cloudy, often brown and full with surface bio film. There is not bio cycle because of worst filtration. The good bacteria do not live in this type of sponge. Years before used Eheim Pick up, the sponge of this model is very fine, water everything was a clear, everything!
Тhe engineers Eheim canister did a mistake. In my all experience of aquarium hobby never seen aquarium equipped with Eheim canisters and clear water!
Its my conclusion.