Actually, the anoxic filtration system is not a plant filter system. Not at all.
Dr. Novak states that the kitty litter and laterite baskets aren't there as a potting medium for a plant filter, they (the baskets)
are the bio-filtration; the plants are there for aesthetic reasons, only, and are completely optional.
Here's a quote from the KV thread (post #7):
Another KoiVet member also asked me: "What effect does the winter have on the Anoxic Filtration System?" Assuming that the filtration system becomes “non-operational” once plants are removed . . . is a misnomer on his part. This filtration system is not plant reliant and plants are only and enhancement to the filtration system but are not a constituent to its inner workings. The filtration system is bioclimatic and keeps working all year long by attracting positive ions out of bulk water. This magnetic attraction never stops just because of cold weather conditions. What we fond is that when most not all, conventional filtration systems run they clog, and when they clog, obligated anaerobic bacteria will soon turn any Nitrates into ammonium -Assimilatory Denitrification- and ammonium will then have to be converted back into nitrates, this then become a never ending cycle. The baskets also work with diffusion, never stopping, and never clogging by bio-film. It is also a scientific fact that redox will also improve when the filtration system is kept running all year. Some hobbyists that have added the biocenosis baskets to their ponds have noticed a 30-45 mV jump in redox. Even the president of the MPKS can validate this statement, for he has keep records on his redox for the past three years now. He uses such baskets in his pond now, which is an improvement to his already hi-end filtration system.