I think that GCA hit the nail on the head. You went from 75 watts to 225 watts. That's a 3X light increase. So in order to keep your tank in balance, assuming it was in balance before you swapped out the lights, you would really need to add about 5X the nutrients. You are running almost 5 watts per gallon on the tank. You are going to need pressurized CO2 on that baby. Also you will need to hit www.litemanu.com
and get some KNO3 and K2SO4 at a minimum.