The flexible media options used by the AquaClear HOB series makes it much easier to transfer portions of media from one filter to another. This can be useful when seeding new filters. The cartridges and biowheel are limiting in this regard. Limiting but not impossible. In the Marineland filters I've used in the past, I was not sure if I trusted the biowheel to be as efficient as touted. What I would do is get some ceramic media (the one with the hole in it), string some fishing line through it to make essentially a small necklace and drop it in the area between the cartridge and the biowheel. The fishing line makes it easier to remove the ceramic media all at one time as opposed to removing the individual pieces. Once the BB become established on the ceramic media, it can be easily moved other filters as needed.