Hi; I am getting ready to buy one of the new 48" Perfecto Sholights and have a question ! There are 3 types of bulbs available for these fixtures; 5400K, Actinic Blue, and 6700K. I am going to put this over a 55G Freshwater tank and would like to know which bulbs would be best to purchase for the fixture ? Larry Botkin botkin at jorsm_com