To again quote Engs method, "Lee Chin Eng, initiated many of the concepts and techniques that are fundamental to successful reefkeeping. Mr. Eng lived near the ocean in Indonesia and used many of the materials that were readily available to him from this source. "Living stones," which have come to be known as live rock, were used in his systems as the main source of biological filtration. He also used natural seawater and changed it on a regular basis."
If you live near the sea and have unlimited natural sea water available to do regular water changes you can keep even the most unbalance reef system designed balanced. You can even keep a lot of fish alive in a 5 gallon bucket doing enough water changes.
Keeping nitrogen exported with live rock and only a small bioload is easy, it's the phosphates and other waste that slowly build, and nutrients that are slowly depleted, that can lead to sudden failure.
I use to believe keeping a reef system would be easy by do exactly what you stated, using a very simple natural approach.
My thinking now is, "why would I build a compost system inside my home to process waste if I can simply flush the toilet?"........
