Skimmy,
I love your babes with Skimmers!!! You should have a calender with those for each Month. I would buy it!
Years ago we just used good old natural bacterial acclimated by balanced nutrient export.
The use of plants to regulate Carbon dioxide, with water motion, salt water mixed as designed with gas exchange. Skimming has reduced the easy accessed amonia to a null. Reduced the chance of organics or toxins from Fish, invertebrates contaminating aquarium systems. The short of it. Protein skimmers keep our aquarium systems in check with less work.
If you want to learn about systems or Coral propogators that do not use skimming. I suggest you look up Steve Tyree. He uses sea squirts, sponges, etc for natural filtration. If you were closer to me I would lend you his book.