For nutrient export, Santa Monica suggested an algae turf scrubber (+1) which in combination with a sulfur-based denitrification reactor would be an extremely effective means of keeping low nutrient levels in big systems like these. Shark keepers have been using sulfur denitrators for a while now, as solid carbon dosing can be difficult. On my shark system, I've been using kilos of Brightwell's Katalyst BioPellets to combat nitrate and phosphate levels, in conjunction with agressive protein skimming.
Ive also tried several other DIY methods, like coil reactors and others. But the sulfur based technology has come a long way and with the risks aside, it is the most effective method.
But... the ATS is a nutrient removal method that has been used in waste water treatment plants on a massive scale. As well as other algae-based nutrient removal methods on the commercial level.
At Inland Aquatics, all of the marine tanks are filtered through in-line "dump-bucket algae scrubbers" exclusively. BlueZooTV has featured them in several videos on youtube. Heres a link to one of the vids, and at about the 3 minute mark he starts discussing the Algae Turf Scrubber that filters their warehouse.
https://www.youtube.com/watch?v=wsVEVUfVtcM
Hope this helps!