I'm noticing it's using old school, 5 MM diameter LED bulbs, not the new brighter surface mount emitters. This can't have have a good lumen output.
Amazon carries this for a little more..Amazon.com : Deckey White+ Blue Aquarium Fish Tank LED Light Universal Extendable Bracket LED Fish Lamp : Pet Supplies
It's getting good reviews.
I noticed a new A23 size household LED bulb on Amazon with 6500K color. 9 watts and 1100 lumens. It will still need a reflector fixture though.For that price even two of them may make it worth buying instead of building one.