Does anyone know of a site that lists the PH of rocks?? I was going to add some rocks to the tank but decided to test them first.. glad I did. Sandstone PH 6.0 Concrete PH 8.? Unidentified Reddish rock PH 6.5 ------------------------------------------------------------------------- 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. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!