Marsilea minuta, like HC and glosso, will eventually start growing on top of each other, building up a much too thick ground cover. I grew it in a high light, CO2 tank, and experienced that. It became a nuisance to me over the year or so that it took to do that. But, there is no reason why you couldn't give it a haircut like you have to do with HC, and control its thickness that way. I'm thinking of dry starting a carpet of it for my next low light tank build.