the XM 20k DE bulbs are going to be extremely blue. you CAN use those bulbs if you want a very blue look to the tank. a fixture will come with
actinic supplemental lighting (usually
T5 or
PC lights). the reason that i recommend the Coralvue Reeflux 10k bulbs is that they are the most white bulb available,
IMHO, and by already having the built in
actinic bulbs in the fixture, they will give you a somewhat bluish white and super crisp look to the tank. not to mention that 10k bulbs are proven to be the best k rating for coral growth.
