Watts-wise, that is a lot of light for the standard 30 US gallon AGA aquarium size. It will be a very demanding environment to maintain. The usual 30 US gallon aquarium is 16 inches deep. What type of 30 gallon do you have that is 19 inches deep?
You didn't mention whether you have a CO2 source. DIY CO2 at that wattage would have to be very consistent to maintain an algae-free aquarium. There is not much "wiggle-room" (as Mr Barr would say).
110 watts, 2 x 55 watts (in my experience, and can grow anything), is a good number for this size aquarium.
It depends on how high the light is above the water surface, what you want to grow, how much time you have to maintain the aquarium, whether you will be on holiday many times a year (leaving the tank to its own devices or to a tank sitter), what the substrate is like, and more.
Good luck if you decide to go this route.
Andrew Cribb