um well u want that bubbler on 24/7 i dont know where u read other wise. you need oxygen at the roots all the time. no they dont need to be submerged, but you can and then once the roots are situated you drop the water level. Its up to you, the bubbles should splash up on the medium when ur water level is just under the netpots. The vaporizer is a good idea, great idea, however i would be careful as to how and how much ur using it. You dont want moister build up any where but under your humidom.