I started out with two Emperor 400. I used Eheim subtrate in the reusable media cartidge and took the AC out of the floss cartridge. It did an okay job. Now I use a wet/dry sump and my water is crystal clear. I use fine media sheets in the drip tray along with the micro pad.
For my other tanks with AquarClear 70 HOB, I'm testing Seachems Purigen for reducing organics and polishing water. I'll let you know how it works out. It may turn out to be a good alternative for your canister.