Back to the original question, I have run my reefs with massive algae filtration without GFO in the past. At times, Particularly when I get a bunch of new fish and feed extra heavy, I add some GFO the help with the increased PO4 input. I have seen no evidence that GFO is in any way bad for Acros provided you don't drop levels too low, too fast-- and the same applies to any nutrient reduction strategy.
And to some of the general points in this thread-- novice hobbyists are best served doing their research so they can ask informed questions that yield sound decisions. Then find someone whose tank is really thriving and not overly complicated and emulate what they do and stick with it. People way too often, make way too many changes based on way too little evidence. The most successful hobbyists I know rarely make significant changes in approach or methodology and when they do, they do so in a slow and methodical way.