I used to, but they're always at zero. Once in awhile I still check them. I also started toying with a small skimmer today more for oxygenation than filtration, but we'll see how that works out.
It's one of Innovative Marine's old models, but with a wood airstone rather than the pump that came with it. It's doing perfect so far. Making a nice foam head but not creating any skimmate yet.
