I agree with Helen, either your filter is not mature or you have too much bio load for the filter system you are using. Personally, I use large sponge filters in small tanks. It works well for me. Mike Wise Cory and Susanne Williamson wrote: > I was asking about the bare vs tanks with > substrate, because I seem to have had trouble > with ammonia buildup in bare tanks. Cory ------------------------------------------------------------------------- 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"! ------------------------------------------------------------------------- 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"!