I keep a boring, bare bottom discus tank and the only algae I've had in 2+ years is some brown algae on the bottom that grows mostly between whole tank wipe downs every week or so. 100% tap water (which is very hard, high pH here). For the majority of that time I've done daily 85% water changes. And there's emergent pothos plants that suck up any extra nutrients in the water. I've never tested nitrate above 5 ppm. My planted tanks always have algae (every tank does). But with enough plants it remains pretty clear.
Do they cover how long that guy has had his tank setup? Seems like a lot of these really beautiful setups have been setup for weeks or months and then you don't usually see them having been around much longer than that.