i've seen people w/ large tanks (above 400gal) invest in these filters .. most of us owners of 240gal or less pay little attention to these filters due to cost ... plus most canister and wet dry filters out there are adequate to take care of the load ... i have a canister, power head and gravel now ... which is very adequate .. my water quality would not be at the level today if i did not have gravel ... however, with the ultima II you can have bare tank and still do well in the water quality department ... cleaning is also easy w/ the ultima II ... a turn of a valve and all your debris will be washed out in minutes .. currently, i spend an hour vacumning and refilling the tank every week ... even that did not remove 100% of the fish/food waste collected over the week ... anyway all of what said above about ultima II is from reading their literature .. i have yet to get an honest opinion from the end users .. just want to see what others have to say ... i'm still waiting for comments .. =)