I placed my Fluval 406 external filter a few weeks back, and now I am wondering if the default filter selection is optimal.
The filter came with 1 bio sponge, 1, bio balls+carbon, 1 carbon, 1 polish trays.
What's the contents of your filter?
I was considering replacing carbon with Purigen and adding phosphate removing medium.
With my Fluval 306 I use the following media with great success: 4 course pre-filter sponges, bottom basket the stock foam pads, middle basket- Seachem Matrix biological media, top basket- micro filter pads with Seachem Purigen on top (1 side) and filter floss on the other side and on top of the Purigen.
I have a sun/sun 304b and use bio balls and ceramic noodles only. I was using the fine floss pad but with the plants and amount of fish i have i found it got clogged and slowed my flow down to quick for comfort. I have a ghetto powerhead with filter floss in the intake tube used purely for water polishing, but even then thats not necessary unless i move plants around so for the most part its not even used. I could probally do away with the filter floss powerhead by adding a coarse sponge to the bottom tray.
In my 306 I have 1 (bottom) Stock coarse sponge; 2) Fluval Biomax; 3) more Fluval biomax with polish pads on top. Every time I clean it I consider removing polish pads to improve flow, but ultimately end up washing them out and putting them back in. Not really sure why, they just seem good to have in there somewhere in the system...