hi,

really for the lighting side of things you should have t5s minamum to give the lumanair qualities for your corals to survive, i am very surprised a shop sold you t8s for a new marine set up.
it takes a long time for your tank to cycle your nitrates will go high and low then stable out as will your amonia calcium phosphates etc your tank will go through changes brown stage green stage etc before settling down what kind of filteration are you useing just out of interest