I wonder if something like this could work? It's what I'm thinking about doing to create a kind of swamp-moss-terrarium.
The wall in the middle would be completely water-permeable and merely meant to keep the substrate in the right-side half (I'd probably also have to use a water-permeable substrate, I guess?), and I would need to adjust the water height and regularly re-fill it, but apart from that, it should ideally be relatively easy to sustain?
@phseiff IMO more is always better, but if you're worried, you could always do a short desc, followed by a longer one with a label for each. I think most people expect it when seeing your posts though because yours are always so good.