Hermit crab crawled out of shell and has been in pool all day

TL;dr One of my three crabs has been out of her shell for at least 24 hours and she’s soaking in a salt water pool naked. I have three new shells around her and she hasn’t taken yet. I haven’t gendered my crabs. She’s moving and her antennas have activity. I haven’t disturbed her whatsoever and even covered the tank with a black sheet to give her privacy. Is there anything else I can do?

Context: I live in Albuquerque, New Mexico. Since bringing my three crabs home from pet-smart keeping them comfortable in this dry climate has been challenging. I’m new to caring for hermit crabs, got these guys last fall, and have relied on this sub and chat gpt for tips on giving them the best habitat possible. One of my three crabs was out of her shell today and is in one of their pools. One of my other crabs seems concerned for her and was sitting by her earlier. I did not have empty shells for my crabs to swap shells in initially, that was my first mistake. Unfortunately my pet store only had these neon shells. I know non painted is optimal. I have two humidifiers next to their tank, I spray distilled water into the tank as a mist every two days and not directly on them, I haven’t since seeing her out of the shell as I’ve read not to spray them directly. When I change their substrate I have it minimum 3.5 inches in depth and did mix the Home Depot play sand with distilled water. Despite all of this, I believe my crabs need more humidity.

Any advice on how to help her get through this and into a new shell and to prevent my three crabs from experiencing any discomfort in the desert would be appreciated. If any of you by chance are in Albuquerque feel free to DM me. I’m worried I’m not cut out to be a crab dad despite how much I care about them. I just want them to be ok. Thanks.