Pretty much with the current selection of bulbs (this may change soon). Most people with a 4 bulb setup would go with either 2 Aquablue specaial and 2 Blue+ (also called Actinic+). Or that same array but trade one AB for a GE 6.5k daylight. With only 4 bulbs, I would probably go with the first option. That will give a very white look with a hint of blue. Whatever you do, dont waste your time with the Pure Actinic...those are no good.