The tank was a 65gal reef ready bought used, so there is drainage in the bottom. I didn't bother with a drainage layer you see in some vivariums. After some testing I found our mostly sand substrate drains readily by itself. I simple covered the bulkheads with a layer of filter material, followed by weedblock fabric, followed by craft mesh to keep the crabs from digging into the filter material.
The saltwater pool is on the left and on the right is the freshwater pool which is a small 1 gallon fish tank with live aquarium plants. The water plants are an experiment, so we'll see how that goes. The wood is mopani. The crabs really loved the big salt water pool. They were in and out it a lot when I first put them in the new tank.
The water pools are supported under the sand, by my pvc contraption in the second picture. I also put craft mesh zip tied on top of it. This is another experiment, but I have high confidence in this one. Now if the crabs tunnel under the large water pools they won't tip and spill. I should also be able to remove them for maintenance without disturbing any potential molters underneath.
The 3rd pick is a DIY foam and grout cave that I'll add later. It needs to wet cure for a month and then it needs to be soaked in mild acid (citric) solution to adjust the ph. It's sitting in a plastic bin now covered in damp paper towels and it has to stay damp for 30 days (probably overkill) to fully cure. I'll probably fill the container with water soon once I'm sure the grout is fully set. It will take up about 2/3 of the back wall. I'm probably over thinking it, but I'm following the instructions for aquarium builds to be safe.
I also still want to add some live plants. Probably small ferns and a pothos. Also thinking about getting /making a magnetic shelf for more climbing area.
Thanks for looking.
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