Your tap water may or may not be fine for a FO
tank. RLG is hinting at the potential phosphates in your tap water, which would give you fits of cyano
and other true algae blooms.
Then again, you may have no problems. Regardless, the filter isn't gonna be worth while. Carbon doesn't strip nitrates or phosphates or chlorine/amine, so you'd still need Amquel (though I recommend Prime over Amquel).