Canister Filter BIO media
 

OK I have a 3 basket canister filter and the way I have it set up is:

Top Tray - BIO Balls with sponges in them
Middle Tray - Ceramic media
Bottom Tray - 3 layers of foam filter material

I think I read somewhere that BIO balls shouldn't be used in a canister filter?? I can't remember if I got that right or not. Can anyone suggest the way I should have it set up with the media? TIA!

The ceramic disk media should be the first through which the water passes, as this media is meant to remove larger debris so it won't clog the finer media like the pads.

Some sort of pad should be last, the finest filtering, to remove the very small particulate matter suspended in the water.

Biological media is not really needed in well planted tanks, but it can't hurt if this is all there is. Without plants, it is very useful.

Byron.

I am assuming the water exits from the bottom of the filter?
I wouldn't think it's necessarily it's bad to use the bio balls, adds surface area, but I'd either switch it out for more ceramic media (perhaps a more "coarse" layer to trap bigger stuff when water first enters the filter), or add more foam material. Do you have differing foam layers (fine and coarse?).

Just noticed I misunderstood the bio media. In my response I was referring to "bio" stuff like Fluval's Bio-Max or the Eheim lava rock or ehfisubstrat. I myself would not use what I think you mention in a canister, but that is just my non-technical opinion.

Bio-balls are only really suited for wet/dry applications and don't really belong in canisters.

Porous ceramic bio-media should only be last in a filter or next to last followed by filter floss for water polishing. You don't want detritus plugging up the media. The EfSubstrat non-porous ceramic media is something else that only Ehiem filters use as a course pre-filter. It should not be confused with ceramic bio-media.

Typical setup is foam, chemical adsorbant (activated carbon, purigen - optional), bio-media, floss.
For bio-media, Bio-Max or Matrix are good choices for canister filters.

I think the terms might be mixed here. You got me thinking so I checked. The ceramic disks are first to allow for removal of large bits, Eheim calls this Ehfi Mech media. Then there is a blue coarse pad to further remove stuff. Then the biological media which Eheim does call Ehfi substrat, it looks like porous white rock. Then the polishing (very fine white) pads.

Thanks for the clarification.