I use a plastic butter tub or coolwhip tub filled with coarse arogonite for my mushroom "pizza slices" during propagation. I place them in the tub, cover it with Tulle (wedding veil type stuff from a craft store) and wait about a month. I then take them out and super glue them to baseball size rubble for trade/display. You do need to keep them out of strong current for at least another month because they still won't be firmly attached and one might fall off, but the process is pretty straigh forward.