Well, growth requires food, and all the methods you said you tried actually remove food from the water. Some people will argue that carbon dosing creates bacteria (which it does) which feed the corals (which they do), but skimmers remove bacteria, so you are back to square one.
All you need for natural reef growth is free-circulating water in your system (no mechanical filters of any kinds), and your scrubber. The scrubber will also supply what algae supplies in the ocean: Vitamins, amino acids, etc, so that you don't have to dose them manually like other people do. After all, in the ocean, algae does all the filtering and all the feeding. 100% of it.