Liv
you will need to consider your tank location, is it airy etc....
There will be a lot of heat from MH especially in a enclosed tank.
1. If for MH light, preferably 2 units, what sort of power shld i look for? 150W per light or more 175/250?
- 250W will be more suitable for SPS in future.
2. If using commercial spot light or so called flood light, what sort of power to look for?
- no idea. would not explore this if I am you. There are already several MH options out there.
3. There is this something like 14K/18k? light intensity? If so, base on the above what do i loook for?
10K - white, better growth, corals look more plain though
20k - more bluish, slower corals growth, make corals look more luminous.
14k - inbetween.
4. Can LED actually replace MH for the same purpose and can it have that sort of shimmering effect
Yup... some of the have been using LED for SPS for some time already.... there will be shimmering effect but not like MH ones. LED shimmering very slightly less intense than the MH shimmering effect.
hmmmm.... personally i would put my $$ into LEDs.
MH sets will also be very difficult to sell off in future.