Are you doing a barebottom? To be honest, the flow required for a bare bottom to be necessary would most likely damage most nems. If you're just talking about the sand height, I personally just mound the sand around the base of the nem. The glass method works well for really big nems, get something attractive (like an old amber glass jar or mason jar) and fill it halfway with the sand of choice (finer is better). Make sure the jar has a top opening wider than 3-4" for the comfort of the nem. Place the nem inside, and it will burrow to the bottom (or even stick to the side) and fill the jar with the foot, leaving a majestic bouquet of tentacles flowing in the water above it! This method also makes relocation really easy.I'm starting a nem tank and I've been thinking more about making it LTA but the sand bed thing is a bit of a deal killer. How tall would the glass have to be?