Clay substrate? Topsoil?

[magikalkoi]

From what I've read, 5:1 sand:cocofiber is the consensus. I'm not satisfied with that though; I want to know if we can do even better. I know ABG mix is bad because the crabs can't seal off their tunnels adequately, but what about clay? As long as the clay is damp it should be moldable, and it's not like it'll dry out. Bentonite cat litter is also used to trap smells, so it might help hermits molt free of predation. I'm thinking a mix with sand, cocofiber, and clay in about a 5:1:1 ratio, but obviously there would need to be experimentation involved.

On another note; what about substituting cocofiber with topsoil? According to Wikipedia, topsoil usually extends 5-10 inches, which is about the depth of our substrate, and it houses a high concentration of bacterial and entomological activity. It may prove an aid in bioactive setups. However, it does have a lot of nutrients which may foul in anaerobic conditions. Instead of substituting, maybe just a short layer on top would be best. Thoughts?

[curlysister]

You won't make the substrate 'better' by adding soil or clay or anything else like that.
'Best' is coco fiber and sand - it can be all one, all the other, or a mix of the two in any combination. Why are you not satisfied with that? Crabs have lived for decades in captivity with that substrate.

[wodesorel]

So, crabs are a little unique in that they require aerated, moist and deep substrate in order to thrive, but it also must hold its shaped when squeezed to allow for the construction of temporary tunnels.

While they do backfill their tunnels, they need oxygen and should never be "sealed" underground in the way you are thinking. ABG can absolutely work so long as it's at a constancy where the crabs can create their own tiny caves underground. ABG tends to be fluffy for better root growth and used much more shallowly than crabitat substrate, as it can grow anerobic bacteria easily when compressed by weight. Layers and screening also do not work with crabs as they are very destructive and kind of stupid about safety.

Moisture is also important as when they shed they become hello for a couple of days. Moist substrate allows for high enough humidity without suffocating or drowning as there's still relatively good airflow. Heavy clays wouldn't work in this manor. Keep in mind too that there is already some clay in playsand - if you were to rinse it (when using for hermits, don't!) you'll get clouds of thick reddish dust that sticks to the sand grains. That helps with holding the mass together when used straight from the bag.

Topsoil is something I've experimented with, along with peat moss. I don't recommend it. Aside from the risks (I ended up with contaminated organic bags that killed off the majority of my emperor scorpions!), crab exoskeleton is different than insect exoskeleton. It's more porous and dissolves easier. Soils rich in organic matter will stain hermit exoskeleton almost black, and cause texture issues. Probably not harmful, but the crabs will look awful while they are forced to live and molt in it. I went back to straight playsand and have been using that happily for over a decade now because it works.