The expert Leonard Stern is referring to is Peggy Hall, aka The Headmistress. She wrote a book on the subject: "Get Rid of Boat Odors" <https://read.amazon.com/kp/embed?asin=B01BW2ZSTW&tag=bing08-20&linkCode=kpp&reshareId=SZ9R8KVBWFWN7FNNKKPN&reshareChannel=system> Raritan republished a test that appeared in "Practical Sailor Magazine." <http://raritaneng.com/pdf_files/Marine%20Elegance/PS0211_ElecToilets_reprint0211-4cWeb.pdf> Raritan stood out. Chris Byer