I can't imagine a single snail shell affecting pH unless your water has no buffering capacity (alkalinity/KH), but you might want to remove it and see what happens. Since we don't know what you do to your water or its original parameters, it's hard to say what is happening. Mike Wise Eric Martina wrote: > Hey all, > In one of my 10 gallon tanks the pH keeps going up. ------------------------------------------------------------------------- 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.