You can harvest GHA just like any other algae. It grows well, pulls nutrients. It's only problem is it's ugly. But then again.....it's in a sump which is usually hidden. I have both growing in my sump area.Thanks! Refugiums was the first thing that came up when I first started researching this issue. I feel limited by my biocube in that regard. I plan on trying chaeto in the middle chamber, if I cant get this under control. But I have heard mix reviews about whether or not I can grow enough chaeto in the limited space to make a difference with my nutrients export.