HCA: Hermit Crab Association

New crab mommas here.
We have four purple pinchers. We’ve had them for around 2.5 months.
Crabittat setup as follows - Tank temp is at 80°f and humidity is at 80%, substrate is moist without being soaked, the substrate is approx 5 inches deep, substrate is a mix of sand and hermit crab bio bedding, bio active substrate.
All four hermies have appeared happy, active and social, pairing up into couples. Eating well drinking well and bathing regularly.
However a week ago 3 of them buried themselves and 3 days ago the fourth buried herself.
Are we doing something wrong? Or is it possible all four have just decided to moult in sync?
We’re absolutely fanatic about making sure they get what they need so have had a variety of complete meals topped with add ons, plenty of calcium etc.
no smell is coming from the tank, no mould etc.
we’re just hopefully being over cautious and panicking over nothing, but I thought I would reach out to y’all for some reassurance and guidance.
Thank you so much.

They're probably just molting: no need to be worried unless you have a flood, bacterial bloom, etc.

While you have no crabs on the surface, it may be best to feed only dry food so you won't have to change it out as often.

Thank you so much for your reply.
We figured they just hadn’t had the right conditions and now they do that they felt safe and healthy enough to molt.
We have been changing water daily to ensure no mould growth and have dried food on the surface. This is just all new to us and we’re kinda those "helicopter parents" thanks again for your reply we really do appreciate it.

Not worrying when crabs are underground is the hardest part of having crabs!
Don't panic about the water - honestly you could probably go a week without changing it (that's all I do, even when mine are both up LOL). Same with the food, just leave enough there that they have something when they come to the surface - and you can probably leave that in for a week too!

Question curly:

Do you only change the water once a week with or without a bubbler?

I'm not sure about Curly, but I don't have any bubblers and I change my water once/week (unless it gets really poopy or sandy, then I'll change it out before).

Sent from my Moto G (5) Plus using Tapatalk

Yep, same as CL77, I only change it once a week. Bubblers don't change how often you need to change your water, despite some people thinking that. Only filters do.

Thank you so much for your replies.
All 4 babies are still down and still no smell etc, so I’m thinking all are moulting which is pretty wild.

UPDATE
2 out of 4 babies have emerged from their first molt
I just wanted to take a moment to thank each and every one of you who took time out of your day to reply, we really really appreciate y’all.
The two still under were a fraction larger than the two that have emerged, so we estimate at least another week or so until they emerge.
One thing I never thought we would be doing is sniffing crabs or asking one another ‘have you sniffed the crabs today?” This crabby world is bankers but I would not trade it. Love our shell babies. Thank y’all again for helping us through this process 🥰

Right on! Glad to hear two have come up! Fingers crossed for the others too!