lighting question

[Terry4494]

I want to convert my FO Tank to a reef tank... and I would like to know how much light do i need. I am not sure of what all i would like so I was wonder what would work the best so I do not need to upgrade in the future... I have a 120 gallon that is 60x23x18

even just a good rule of thumb would help like how many K per gallon or any equation so I can at least get started planning

Thanks

[dvarner32]

The question that needs to be answered first is what kind of corals do you want to keep.