HCA: Hermit Crab Association

So im Fairly new to crab keeping and recieved my crabs from a friend who could no longer house them. They were pretty active when i first got them and now theyve both gone under the sand. I understand that they burrow, but typically for how long? Its been about 2 months for one and 3 weeks for the other. I have sand and coconut fiber and sphagnum moss for sub. Im just starting to worry about them honestly... </3

I wouldn't worry until at least four months.
Are you sure they aren't coming up at night when you don't see them? Many crabs do spend their days buried, and only come up at night. Also, they will sometimes come up just for a short amount of time, then go back down again. So they may not have been down for the entire time you think they have been.

Should I keep food in the tank then? And I've been spraying it normally still too.

Yes, definitely still keep food in the tank, make sure to replace it every few days so it doesn't get moldy

About the food: if you only put drier stuff in there while you're not seeing any hermies, you won't have to change it out as often. It will take longer to mold, get stinky, or attract bugs.

Also, you can smooth out the sand with your hand when you go to bed, and if there are tracks in the morning, somebody was up. I also like to put plastic lids precariously on my bridge that will fall down if they get touched.

Be cautious when spraying, that you don't spray too much and cause a flood. Do you have a thermometer and hygrometer to monitor the temp and humidity?

I'm fortunate that I live in a climate where I don't get bugs in my tank. I leave the dried food in the tank until it's moldy when I don't have anyone up. The mold won't harm the crabs, I just change it when it's fuzzy LOL.

They still haven't come up, and their food isnt being touched. Are they okay?

In that case they are probably molting. After like 4 months when they went down check if they are dead if there is a fisjy smell. Otherwise they might just be having a long molt.

I have larger crabs that have stayed down for 2.5 years! It made for a pretty boring tank when all six were under for about 4-5 months.

I feel like there is no point in digging. If the crab died, you can't save it and it's not necessarily harmful to the other crabs. If it's alive and molting, you can kill it by digging it up at a delicate time in the molt. It's hard, but wait it out.