fluval 404 foam block media

[henners]

Hi, I noticed in the side slot it looks as if I can fit 4 foam blocks for mechanical filtering. Was it designed for 4? If not, is the 2 that comes in one box supposed to go on the outer side or on the inner side? I can't tell because they both fit. But I have it on the inside right now, but want to make sure it's actually filtering and not getting bypassed. :help:

[maxthedog123]

It's 4 foam blocks, and I think the 2 pack fits both inside and outside.

Rinse them out in aquarium water (not tap water) when you clean the filter to get big chunks/debris out of it.

If you do need to replace them, try to only replace 2 at a time so you don't get rid of a bunch of bacteria.