Freshwater Refugium bio-mec. Filter

[jamesfoad]

I have a job filter and I want to make that a refugium that uses both biological and mechanical filtration. I know SW tanks use these but why wouldn't it work for FW. If anyone has I dead or videos it would be much appreciated. Also I couldn't find usable info on the posts about it here on AA

 

[flyfishfan1966]

Here's one I made each "bio tower" has mechanical then bio filters.