The time is near to replace my bulbs. Currnetly I have three fixtures suspended above the tank @ 12" with a tank depth of 30" on my 220 gallon. I have my ballast currently set to 400W, although it is selectable to 250W as well. The bulb is a single ended mogul base type bulb. Was thinking 20000K...(or maybe like 14000K in the middle fixture and 20000K on the ends). After some suggestions both on manufature and arrangement of bulbs.