snail shell are mostly calcium carbonate which would slowly dissolve in the water. Can it alone be responsible for your pH? Well, get it out , do your water changes and you'll know. take care Yvan Alleau 712 N.W Kings Blvd Corvallis, OR 97330 College of Oceanic and Atmospheric Sciences Oregon State University office (Burt 222) # 737-3649, to be used wisely! yalleau@oce.orst.edu ------------------------------------------------------------------------- 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.