New Biodenitrator

[Delphinus]

Yes I agree that makes more sense. Like I said though the DIY instructions Carib-Sea talks about looks like single-pass to me, .. you can easily replicate the anoxic zone with a slow enough flow without the recirculation, but I agree it seems easier to do so with recirculation. If the channel was long enough I guess you could get away with it. But anything I would want to build I would want to make it as recirculation because anything that increases contact time cannot help but help.. whether it's a skimmer, reactor, heck even my Phosban reactor I'd like to modify and make recirc.. it just makes sense to me.