While I have been importing the caresheets for CSJ I was looking over the list of ‘essentials’ for getting started and questioned the importance of sponges. I conferred with Michelle and she agreed that they are more trouble than they are worth and really should not be on the essentials list.
Sponges CAN help raise your humidity but there are better, more consistent ways to do this.
Sponges need to be kept clean or they can lead to the growth of mold or mildew which can be harmful to your hermit crabs. This means they have to be taken out daily and washed thoroughly in dechlorinated water. Once a week the sponge should be thoroughly washed and left to dry out completely. So you need more than one sponge to be able to rotate them. It is recommended you boil the sponge or once it is dry you put it in the microwave for a few seconds. For a kid this may be a bit much to remember and for an adult it’s extra steps that just aren’t necessary.
If you want to leave a dry sponge in the crabitat for the crabs to nibble on that’s a good use for them. I just don’t consider a sponge to be an essential item in crab care these days.