That sounds like quite a good idea Mark...definetly worth an investigation.One possible way I have thought of, but not used as yet is to create a false top rather than a false bottom. Fill the tank with sand to the depth required and mix in 1.5% water by mass, then cover the sand with glass or wood so it fits tightly in the tank. The wood should have a hole or two for a burrow entrance. Cover the wood with sand for looks etc and allow to dry to make it hard/stable. Have something poked into the soil through the hole so it can be located easily. Once dry, dig it out a little to allow the scorpion to find the right place to dig, clearly it wont be able to construct a burrow elsewhere. This method should trap water in the soil at the right levels and disallow water loss via evaporation.
This is from my own area, you would need to establish some idea for each species, although with sand in general this figure should easily give rise to a good humidity gradient and have it feel nearly dry. It doesnt take much water to create humidity.You mention a water content of 1.5% which i'm assuming is the mean average water content from your own area, or is this a general desert average?
The idea is not to dry the soil out, you want the soil to have around 1.5% finished. If you pack the soil down hard and use a false top it will hold a burrow easily...at least the desert sands I use do.Would you not have to add more than 1.5% water if you wanted a water content of 1.5% when the soil was dry.?
I'm not sure why you would want to dry the soil out. 1.5% is virtually dry as it is. How are you going to generate humidity if the soil is dry? I use 1.5% because that is the water content of the soil at the maximum burrow depth, above this it is drier in summer and wetter in winter. After rain it reaches about 4% at the surface. I would say I could easily get away with 1% to generate the humidity.I think your false top system might be worth setting up for my O.wahlbergii. Although i imagine it'll take quite a while to dry out before the scorpion can be introduced.............................
Alright, i'm with you.I'm not sure why you would want to dry the soil out. 1.5% is virtually dry as it is. How are you going to generate humidity if the soil is dry? I use 1.5% because that is the water content of the soil at the maximum burrow depth, above this it is drier in summer and wetter in winter. After rain it reaches about 4% at the surface. I would say I could easily get away with 1% to generate the humidity.