Hi Here are some books that I like and use: * Water chemistry for the advanced aquarists by Guido Huckstedt (original in German but bought this english version from Lee Finley in the states) * The Aquarium Encyclopedia by G=FCnter Sterba Some I don't own but htey are supposed to be good and accurate: * Akvarieteknik by Guido Huckstedt (in German) *Handbuch Aquarientechnic by H. J. Krause *Handbuch Aquarienwasser by H. J. Krause KrA - -- Kristian Adolfsson Malm=F6 Akvarief=F6rening, http://www.roka.se/maf Nordiska Ciklids=E4llskapet Guardians of Catfish Nobelv=E4gen 147 M:22 SE-212 15 Malm=F6 +46-(0)40-188556, fax 182133 ka@roka.se