beviking - I run over two dozen tanks, most planted, each designed for that particular place/planting scheme/fish. It is shooting yourself in the foot to do work that does not need to be done. Dealing with modules (sponges in this case) is easier, faster, and more consistent than dealing with bulk supplies (floss - is it too much, not enough, is it packed evenly, just right? Is it all in or is some dangling out?). There is a difference in working systematically and efficiently on multiple tanks, and doing from-scratch on a few. This is the same reasoning as my separation of bio- and mechanical filtration - it is far more efficient and effective. It certainly uses more equipment, but it makes upkeep a snap. A bit of upfront planning and systemization is needed to run multiple tanks well. Certainly I could operate many of them with multiple corner box filters with carbon and floss - I do remember when LFS operated that way, but it would not look as good, and would not operate nearly as well for many fish. My wife would rather strongly object to the "look" and noise as well - keeping the spouse happy is no small thing when there are tanks all over the house. We are in agreement that tanks should be seen and not heard, and that routine maintenance should not involve a big mess in the area, or hours of time.