ive been using boiled tap water for about 3 months now, no problem...just boil it, let it cool, then add some amquel...my tanks doing fine...once your tank is up, to do water changes or whatever, go to vons (safeway in the bay area...) and buy some safeway brand distilled water..."prepared by reverse osmosis and/or deionization"....perfect to add to the tank....very convenient too....