I used to make LED lights, the difference between the mariglow and AI or Radion IA in the LED diodes themselves. If you got enough mariglow fixtures you would be able grow coral in a shallow tank. The spectrum of the LEDs is probably fine its just lacking intensity necessary for a tank taller than 8". Its like comparing a little keychain LED flashlight made up of 15x tiny white LEDS and two AAA batteries to a CREE single LED flashlight running on 4x AA batteries. Besides 10x the price theres probably 10x the distance you can see with it.
The CREE and osram LEDS in the big names are going to much brighter and run more wattage through each individual LED . This allows the lights to reach deeper into the tank. They also do it for more lumens per watt, and by a significant amount. 100w of mariglow might not even translate to 100w of high quality LEDs, you might only need 80w of the high quality to reach the same light intensity as 100w of mariglow.
If you want to save money look into someof the other black box LEDs available. The noopsyche on here and MARSaqua and other brands offer lights that are proven to grow corals at huge discount. They are not all running UL listed parts and vary in design quality but they seem to grow coral regardless.