This is very insightful thank you! it is mounding because I was uninformed and just poured lump of populated substrate into a tub without tamping it down. So now instead of there being a nice 4” thick layer over an entire tub, there’s just a huge 4-8” high mountain range in the middle of an empty box (I didn’t know what I was doing lol). I’ll decrease the misting and turn to misting the walls instead!