standard florescents do come in 50/50 but they are pretty rare and its suggested that you instead buy one blue actinic bulb and one 10,000K pure white bulb. if you are trying to house corals in your tank, it is recommended that you have both to offer the corals a full spectrum of light. coraline algae will grow with both, but if you are looking to have alot of coraline, you can try calcium or other supplements such as Purple-Up instead of basing your lighting off the coraline. hope it helped a little
reefman