I noticed that my substrate has been getting increasingly dry, but I had one down. I saw it up yesterday so I transferred the crew to an empty 20 with a bit of moss in the bottom and wetted down my tank.
I removed all the décor and stirred up the sub really well before and after adding the water. It took 2.5 gallons to get the sub back to sandcastle consistence. No foul odors near the bottom so that tells me I can mist a wee bit more.
Here are a couple of pics I took of the mad crabs, most are pretty blurry and off center. Sorry!
Sulking en masse:

Trying to escape the horror:

Don't touch me/I hate you:

I must bathe the horror away:



I love my crappy old shell/leave me alone:

