Hi Yvan, There has been a good amount of discussion on the Carbo Plus (the carbon bar based system) on Aquatic Plant Digest. I'm afraid that most of the users seemed to have concluded that it is not worth the money for a large planted tank, although it might be different story for small apisto breeding tanks. You can search the APD archives for various people's opinions on this. http://www.actwin.com/fish/aquatic-plants/index.php Tomoko ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@listbox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@listbox.com.