Light placement...

[Taposh Mallick]

How high the lights should be placed from water surface?

 

[Crabs McJones]

There are a lot of variables that come into play. What lights, what size tank, what corals are you keeping, how many light fixtures are you using, are the lights enclosed in a canopy or out in the open?

 

[PDR]

Depends on a lot of factors, what kind of lights do you have?