upgrade in lighting question

[CarolD]

I'm planning to upgrade my 55 gallon reef tank from a Coral Life fixture to the Aqualight Pro HQI which has metal halides. Do I need to make the change gradual? Just wondering if I can harm any of my corals. I'm doing this because I have several hard corals that need an upgrade in lighting.

Thanks in advance.
CarolD

 

[jasper24]

What type of light (PC, VHO, etc) and bulbs do you have now?

 

[CarolD]

I have fluorescents, 2 - 65w actinic and 2 - 10,000k and a moonlight. Thanks again in advance!