I make my own filter/refugium/sumps out of another tank, using a commercial water pump such as Sicce, Mag-flow or Laguuna, and some media.
And the most important filtration component, live plants (aquatic and terrestrial, and semi terrestrial).
The media can be anything from lava rock to Porrett Foam, because beneficial bacteria don't give a rats arse about the composition of the surface area or media they live on.
I find most commercial filters to be inadequate, have wimpy flow rates, and are vastly overrated, and do nothing to effect nitrate. (accept add to it)
The 125 gal sump below is the filter for my 180 gal main tank.

a closer view of the refugium

And as you can see, I break the "rule" about where to place the sump, and oft touted "rule", I don't use compartments.
I find these "rules" arbitrary and of no real relevance, just as I find most commercial filter no more than plastic toys.