Keep any light. Yes they respond more to the reds and grow more in bloom with them but the blue is not going to hurt anything at all. Leave it.Ok I am growing 3 autos under a 250 cfl looking great now using bloom and a week into flowering because there autos I have kept lights on 18/6 all through grow last week I added a red 250 watt flowering bulb shall I turn off the ultra blue cfl or keep it on also ?? Thanks