I use what is known as Iron wood....very dense and heavy, and only needs a rinse before you put it in the tank. I haven't had any problems (yet). I did have trouble with some of that sandblasted stuff though. Leeched all kinds of weird stuff into the water. However , the other day I put a ceramic pot (that had been glazed) into one of my tanks and within 24 hours it was covered with what sounds like, the same gelatinous stuff. One of my Taeniatus got popeye and died. I think this stuff has to be bacterial (I believe popeye is also). I know this does'nt help any, but it's another piece to the jigsaw!! ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@majordomo.pobox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@majordomo.pobox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!