I personally am obsessed with getting my water crystal clear and polished so I though I'd chime in here even though I don't own a canister.
I assume you want water that looks like this:
Crystal Clear Water in Aquarium Tanks - YouTube
How to get crystal clear aquarium water - YouTube
After my "pursuit for perfection," using HOB
's, I found it could only be achieved (at least close) after making sure ALL water in the tank passes through 100 micron polishing pad (as well as Seachem Purigen for chemical filtration):
Aquarium Advice - Aquarium Forum Community - Paul1792's Album: Paul1792's 38 gallon - Picture
After downloading the owners manual to your filter, it looks very capable of excellent filtration. I believe that your problem is caused by either or both of the following issues:
1) water is bypassing the 100 micron polishing pads in the filter
2) the fact that your tank is "heavily planted" is restricting the flow of debris laden water to the intake
on your (relatively) large tank (I think this is the problem).
If you are sure it's not #1, you could always try this:
Aquarium Filters & Filtration: Fluval Multi-Stage Series Water Polishing Pads
which gets you down to 60 microns but is labeled "not for continuous use."
or putting on a pre-filter - "filter sock" on your intake
Particulates in the the tank - Page 2
However, If you are certain there is no bypass in your filter, I'd suggest adding an HOB
with the intake at the opposite end from the intake on your canister and making sure all water passes through 100 micron polishing pads. Specifically, I'd recommend a Fluval C4. Although a C3 would do it, the C3 intake only goes half way to the bottom of the tank so you have to buy a $7 extension. If you're going to do that, however, you might as well upgrade to C4 and run it at lower volume for a few bucks more. Note .... before giving myself a nice filter laden Christmas present .... I used a cheap walmart aqua-tech stuffed with custom media including 100 micron filter pads ..... and even got crystal clear water with that.
[Note: I just had a bad experience with aqua clear 50 running side by side with C3 ..... the factory media did not cut it. My C4 on my 29 gallon keeps water perfect ... so I got a second C3 to run on my 38 gallon. I use aquatic life 100 micron non-woven polishing pads in my HOB