First reef tank lighting

[shark777]

First saltwater tank, 29g standard (12x30x18) currently three weeks past cycle. No fish yet but I do have some inverts, green star polyps, and some purple mushrooms courtesy of the 40lbs high quality live rock I added. have some snails and hermits as part of my clean up crew. I think I'm okay with lighting as it stands, currently running two 24" t5s one being actinic, tank is only 18in deep and I have a 4in deep sand bed. However I want a mixed reef and realize I will have to upgrade soon. Hoping to keep some easy corals like mushrooms, zoas, and maybe an anemone or some lps a ways down the road. Thinking about aquatic lifes 30in t5 four bulb fixture but I'm wondering what the clearance is above tank as I have a hob skimmer that may have conflicting dimensions. Any and all suggestions welcomed, thanks in advance for your help.