I've read great things about them like they can replace your protein skimmer. There is a guy on youtube with a KILLER 125 reef stocked heavily with fish, and he says has done no water changes for 4 years just uses carbon and an algea scrubber and he never has nitrate or phosphate issues. And just doses elements.
They look easy to build. I'm considering building one.
They look easy to build. I'm considering building one.