With more people wanting to use natural filtration for their tanks, we are going to look at the two main types of units that you can put on your system: Chaeto reactors (or "algae reactors") and algae turf scrubbers (ATS). We won’t be looking at refugiums however, since those have mostly a different purpose. This will be a multi-part post; the next post will start with the basics, so if you’d like anything in particular to be covered, let us know.