What kind of media do you use? In my canister I use sponges and noodles. In my AquaClear I use sponges, noodles and carbon. The reason I'm debating is weighing out whether or not to add filter floss as well.
Hey, in your canister you could try or research these;
1. Pillow Filling
2. Seachem Purigen
3. Seachem Matrix
1. The Pillow Filling, i buy a cheap $1 bed pillow. One pillow will last me about 2yrs!!. Take the stuffing out, which is basically the same as the polishing pads you buy for the canister. Keep an old pad and give the pad and filling a good rinse in old tank water..Fill the top tray with the filling and put the pad on top(this stops any loose filling clogging your canister)..Will help get/keep your water crystal clear..
2. Purigen, brilliant stuff. Will make your water crystal clear. Also helps with Ammonia, Nitrites and Nitrates.. Just put it in the top try, on top of the polishing pad. Can be re-used by recharging it...
3. Matrix, A bio-media that can be used instead of bio-balls, noodles. 1ltr of this is equivalent to 170 bio-balls(Seachems Claim). Quite cheap and will supposedly last forever!!!..
All three are very cheap, easy to use and will last a long time..As always, do your own research but they will make your water sparkle...I'm not familiar with HOB's, Convict is the man to help you with those but almost any filter can be customized to use any/all of the above..
Hope this helps...Ian