sera Bio Nitrivec (Instant Bacteria)The fastest start up purifying bacteria on the market, this product will cloud up the water for up to 24 hours before turning crystal clear. Premium class liquid filter medium Breaks down food remainders, ammonium and nitrite biologically Provides settling area for useful purification bacteria Creates a biologically active living environment The dangerous toxic substances ammonium and nitrite are being formed permanently in aquarium water. sera bio