Just a quick opinion. I have been running the miracle mud in a small fuge on a 46 Bow with an overload of rock (150+ lbs) and saveral small soft corals and a small fish bio-load without a skimmer. The only reason I haven't been running a skimmer until now, is the 46 was simply a temporary home for my my larger tank until I finished the DIY
parts. (The skimmer I do have is an in sump model). I have had no problems at all. I would have to suggest that size matters. If you are running a large tank tank you should run a large fuge with lots of macro (pruned regularly) and be disciplined with water changes it works great. I have to add that now on the larger tank (72G bow with 30G sump) I am running both. My water seems cleaner in the larger system while running both a fuge and skimmer. But coral growth rate has not appeared to change either way.