Foam as a substrate layer
I have some Poret foam which I got to make a HMF. Could I also use a thin layer of that underneath my substrate (UNS controsoil)? The shrimp like to pick at the substrate grains, and tends to uproot my dwarf hairgrass. I figure the foam would provide a layer for the grass's roots to grab onto. So maybe something like 1/4" foam and 3/4" substrate on top.