Welcome to AA
I used tap water with a conditioner to take care of chlorine/metals etc.. for a while until I could not get rid of my algae problems due to all the junk in the water. I finally broke down and got a RO
unit, I'd recommend one if you are going to be in this hobby for the long run. Wal-mart and other places sell RO
water but over time it will just add up to the price of a RO
unit anyway and you have to worry about lugging water home all the time. If you have the money go w/ a RO
unit, if not I'd recommend buying water and only using tap water conditioner as the last option.