New Crab Carer here, Wanna make sure my setup is good. Feedback needed please

[SpookySoulGeek]

Want to make sure my setup is adequate for the best health and happiness of my crab.

took in a hermit crab for a friend whose daughter moved away and left them. friend cannot care for hermit crab. She needed to find someone to rehome them since they were not getting adequate heat or humidity. Friend's daughter had them since April.

*Current setup:
*hermit crab is approx 2 to 2.5 inches
*5.5 gal tank (have 10 gal on hand as well if they need larger)
*substrate: flukers hermit beach sand with about 1/4 or so coconut fiber mixed in
*medium/large freshwater dish, temporary small saltwater dish (can use a larger one or buy new if needed). Freshwater is regular bottled drinking water treated with reptisafe (2 drops per 8 FL Oz). Saltwater is treated freshwater with Zoo Med Hermit Crab Saltwater conditioner 1 tsp (5ml) : 250 ml (approx 1 cup).
Food: using seashells, I have JurrasiDiet- Hermit Crab Formula and I've put cucumber carrot and kale in.
Light/Heat source is Zoo Med Reptisun 5.0 UVB 13 watt Tropical
Temp stays between 72 F and 78 F approx. Humidity seems to fluctuate a lot but is between 70 and 85 %. I mist a few times a day and keep sand at "sandcastle building" a mount of moistness.
Also have two shells, one a bit bigger than the other in enclosure. Going to pet store later today to get more supplies hopefully they have some shells. They are currently in the painted shelf that they were in when I got them. Hoping he takes to the non painted ones since I don't like the painted ones for health and safety reasons.

I got them last Monday and set them up. I made sure to place them in the freshwater, which they seemed to drink, and the saltwater, which they liked as well. I didn't notice any food being eaten, but could have ate a small portion.

For several days now 3-5 days, They have been buried mostly in the sand, with just a bit of the top of the shell showing. I (mistakingly, before I read online about not disturbing them) took them out of the sand to check in them and placed them in their water. When they initially started digging, before I took them out to check, they seemed to scrape around at the bottom and I noticed chirping or clicking sounds for a bit. No sound or movement save for very slight once in a while.

I have several concerns.

1. If they have been living alone since April, would it be best to get them a buddy, or leave them alone? How do I ensure that if I get another crab that they will get along? Ask, if I do get another crab, I'll switch to the 10 gal tank. I live with my grandparents (disabled adult here), and I'd have to convince my grandma to be okay with me getting a second one if they need a buddy, otherwise I'd have to rehome them

2. How do I know if they are moulting or just unhappy? I'm getting more sand today to that I can mix that with the coconut fiber for added depth

3. With humidity fluctuations, I've got some window screen I can attach to the metal screen top. Any other tips for keeping humidity more stable?

4. Temperature seems to be too low. Would a heated bottom or secondary tropical reptile light be best? Also does elevation help with the air conditioning not affecting this or humidity?

Overall, I want the best for this little dude, whether they stay with me or are rehomed. Also not sure the best place to get shells ethically.

[curlysister]

Want to make sure my setup is adequate for the best health and happiness of my crab.

took in a hermit crab for a friend whose daughter moved away and left them. friend cannot care for hermit crab. She needed to find someone to rehome them since they were not getting adequate heat or humidity. Friend's daughter had them since April.
Curly - Welcome to the site and to crabbing!

*Current setup:
*hermit crab is approx 2 to 2.5 inches
*5.5 gal tank (have 10 gal on hand as well if they need larger)
Curly - Yes, I would recommend at least the 10 gallon.
*substrate: flukers hermit beach sand with about 1/4 or so coconut fiber mixed in
Curly - This is good substrate, but is expensive. You will want the substrate to be at least 2-3 times as deep as your largest crab, and moistened with dechlorinated water. Play sand is cheap from the hardware store, and works really well.
*medium/large freshwater dish, temporary small saltwater dish (can use a larger one or buy new if needed). Freshwater is regular bottled drinking water treated with reptisafe (2 drops per 8 FL Oz). Saltwater is treated freshwater with Zoo Med Hermit Crab Saltwater conditioner 1 tsp (5ml) : 250 ml (approx 1 cup).
Curly - Use tap water treated with a dechlorinator for the fresh water, then use a marine salt to make the salt water. That way, they get both ground and ocean minerals. The Zoo Med doesn't have all the necessary minerals for long term health. Check the 'water' care sheet for full info.
Food: using seashells, I have JurrasiDiet- Hermit Crab Formula and I've put cucumber carrot and kale in.
Curly - Crabs need a varied diet that includes animal protein and calcium daily. Check the 'nutrition' care sheet for full info.
Light/Heat source is Zoo Med Reptisun 5.0 UVB 13 watt Tropical
Temp stays between 72 F and 78 F approx. Humidity seems to fluctuate a lot but is between 70 and 85 %. I mist a few times a day and keep sand at "sandcastle building" a mount of moistness.
Curly - What do you have for a lid on the tank? Something solid, or even plastic wrap, will help keep humidity and heat in.
Also have two shells, one a bit bigger than the other in enclosure. Going to pet store later today to get more supplies hopefully they have some shells. They are currently in the painted shelf that they were in when I got them. Hoping he takes to the non painted ones since I don't like the painted ones for health and safety reasons.

I got them last Monday and set them up. I made sure to place them in the freshwater, which they seemed to drink, and the saltwater, which they liked as well. I didn't notice any food being eaten, but could have ate a small portion.

For several days now 3-5 days, They have been buried mostly in the sand, with just a bit of the top of the shell showing. I (mistakingly, before I read online about not disturbing them) took them out of the sand to check in them and placed them in their water. When they initially started digging, before I took them out to check, they seemed to scrape around at the bottom and I noticed chirping or clicking sounds for a bit. No sound or movement save for very slight once in a while.
Curly - You are correct, don't dig up a crab who is underground. And don't bath them, they will do that on their own.
I have several concerns.

1. If they have been living alone since April, would it be best to get them a buddy, or leave them alone? How do I ensure that if I get another crab that they will get along? Ask, if I do get another crab, I'll switch to the 10 gal tank. I live with my grandparents (disabled adult here), and I'd have to convince my grandma to be okay with me getting a second one if they need a buddy, otherwise I'd have to rehome them
Curly - It's up to you if you get another, they do just fine on their own. A ten gallon also won't be suitable long term for more than one crab, you would eventually need a larger tank as well.

2. How do I know if they are moulting or just unhappy? I'm getting more sand today to that I can mix that with the coconut fiber for added depth
Curly - When they are underground, we dont' know if they are molting, de-stressing, or just digging for fun. Only time will tell. Just keep the conditions good, and wait until they come up. If you are adding sand while the crab is underground, don't pack it down or drop it in from a height.

3. With humidity fluctuations, I've got some window screen I can attach to the metal screen top. Any other tips for keeping humidity more stable?
Curly - Something solid like plexi glass or glass, or even plastic wrap works just fine.

4. Temperature seems to be too low. Would a heated bottom or secondary tropical reptile light be best? Also does elevation help with the air conditioning not affecting this or humidity?
Curly - A heat mat (commonly called a Under tank Heater) mounted on the back of the tank (not under the tank) will help to increase heat without zapping humidity like a heat lamp will.

Overall, I want the best for this little dude, whether they stay with me or are rehomed. Also not sure the best place to get shells ethically.
Curly - Naples Sea Shells is exellent.

[SpookySoulGeek]

Thank you so much for the help. I really appreciate it. yeah that's what I'm going to get to add depth next. I've got dechlorinated water ready to go for when I mist it.

So for the lid, how much space should I leave for air flow? Are there pictures that I can get for a reference?

So it's safe to put the new sand around and on top some as long as I gently place it around/on him?

Again, I'm really grateful for the help. I'm very passionate about my animals (i keep terrariums with inverts and toads off and on) so this is super important to me.

[curlysister]

If he hasn't moved, then yes you could just kind of add some substrate/ sand around him. Just don't cover him more.

I only have a corner about 3 x 3 inches open to allow air flow. Some people have the whole top covered, and figure that the crabs get enough air when the lid is opened to do maintenance, give food and water etc.

[SpookySoulGeek]

thank you, i used a ceramic tile to allow about that amount and it's helped alot, thanks.