I used bio-spira in my 55gal tank yesterday about 2:30p. I took some tests this morning at about 8:00a. and the results are this ammonia = 0, nitrites = 0, and nitrates = 5.0 Should I let the tank sit for a few days or can I do a partial water change? I have 2 dwarf gouramis, 4 zebra danios, 2 strawberry tetras, 2 gold tetras, 2 red tail sharks, and 1 pleco. I am also thinking about moving the danios and tetras to a different tank and adding in some larger fish, any sugestions as to what will live with gouramis and sharks?