Do you need daylight bulbs?

[CandyCane]

I've got a 20gallon reef tank with mixed corals. The fixture I have is running T5 bulbs and it is able to have 4 bulbs total but they've been burning out.

Since the actinic and sun wave bulbs have burnt out, the bulbs left are a coral wave and an aquablue special.

I thought this would have a negative effect on the corals but since the loss of the daylight and actinic my corals have increased in color in a very noticable way along with size and growth rate.

Any idea's why this would be the case and should I try adding more bulbs again or just leave it all as is?

Do you know what the long term affects of having just the blue and wave bulbs would be?