there is no right or wrong answer to the color temperature as long as it is between 12000K to 20000K, you are fine. It is all personal preferences. Some people choose to go with a lot bluer color in their tank as they think it is a lot crystal clear to them, but someone hated it cuz higher in Kelvin means lower in lumens and would not look as bright as something that is 12000K to human eyes.
If you choose to go with MH
, that is totally fine, but understand the additional works you will need such as a chiller and changing light bulbs on time.
I am bias on this not because I sell LEDs, it is because I am a victim of MH
myself due to heat. And I promised myself will never use another MH
for my reef tank from that point on after losing about 20k worth of coral and fish.