[HERMEZ]

Well keep in mind that molting crabs often resemble dead crabs- the exo will be hollow. Dead crabs smell bad so you will know when that happens. The size tanks you have are really too small for the crabs to thrive well. I don't know where you live but you may not need a heater and the sand should be moist. Have you read all the caresheets etc here? You need salt water (Oceanic - Red sea etc etc) and a fresh food diet. Vckums sells all kinds of foods- stay away from commercial foods- do you have gauges- that will measure your temps/humidity