I noticed this today while I was looking up stocking lists...
anyone here have any experience with this type of gizmos?
Heh well... I bought the stuff and am going to make a modified version of that with a removable filtration chamber for carbon in case of sulfer problems (fail safe?).
Going to add it to a tester tank with a messy eater and give it a shot.. Will take a while, but I will report my findings when the time comes.
(and yes, for the record I understand you should remove the source of nitrates, but any dependable measure is a good measure in my book, so we'll see)