HCA: Hermit Crab Association

Sorry in advance for the long post.

I have had my hermit crabs for 3 months, I have done a considerable about of research and am learning new stuff every day. Below are my tank conditions.

20 gallon for three small crabs (quarter size and smaller), they are PPs. I just got a 40 gallon breeder and I am going to upgrade as soon as my crabs are not buried.

Substrate: I have playsand and reptisoil, probably a little more than a 1/5 ratio.. again waiting for my crabs to come up to fix.

Heat/humidity: I currently have 2 UTH and the temp is 75-80, the humidity is 80-90. I have a digital monitor.

Food: I do fresh veggies, freeze dried mealworms, eggs, egg shells.

I have shells galore! I have like 50 turbo shells for them to choose from, yet only one crab has changed.

My crabs have been under for almost the entirety of the time I have had them. The smallest went under first and is still under. One has re-emerged and is staying up, and the last one is the biggest and went under last. The smallest has been under for around two months and I know they can stay under for awhile. I am worried because I have moved the tank and it is on top of my dresser. The pools are not the way I want them and I also want to upgrade. Should I be worried about the crabs who have not emerged? Am I doing something wrong? How long until I should stress?

It sounds like you're doing everything right, they're probably molting. I know usually the larger the hermit crab, the longer they molt, but I think as long as the hermit crab tank doesn't smell like fish your crabs should be okay. If after your bigger crab comes up the littlest crab is still underground, maybe you could dig super gently? Recently my hermit crabs did a similar thing, they were both under for a month or so and I thought they were dead, but I found them and they were both fine (:

If a crab dies underground, you will likely not smell it through the substrate.
Your conditions sound really good.
It really isn't recommended to go digging up crabs. If they are dead, digging them up accomplishes nothing. If they are alive, digging them up can be harmful or even fatal depending on what point in the molt they are in. I would not worry for at least 4 months, and then only if you know for certain they aren't coming up in the night would I consider digging. If you are able to maintain two tanks, you can get the new one ready, and move the crabs over as they re-appear.

Thank you both so much for your reply!