I am going to go through your answers point by point and address the areas of concern:
1. Remove all "desert sand". It is calcium based and is probably what is sticking to him, causing the irritation. The sand is dangerous as it cements crabs inside their shells and pulls moisture out of their bodies. Playsand by quikrete or sakrete is less than $5 for a 50lb bag at Lowes or Home Depot and 1 bag is plenty for a 10 gallon tank. We recommend mixing it with Eco Earth (coconut fiber) about 1/2 a brick to 1 bag of sand. A 10 gallon tank is fine for 2 small crabs but keep in mind that they will grow quickly and will need a larger space soon.
2. Gauges are a must, digital Acurite from Wal*Mart are less than $10 usually. Your heat needs to be at least 80°F at all times. 75°F is the absolute lowest safe temperature. Their natural habitat is in the mid 80's or so year round, and they risk organ damage and death at low temps.
3. Both fresh and salt water need to be treated with a product like SeaChem Prime to remove chlorines/chloramines/ammonia/heavy metals. Tap water contains chlorine which blisters their gills. Salt mix needs to be marine grade such as Instant Ocean or Oceanic. It cannot be aquarium salt, it needs to be the marine grade sea salt for setting up saltwater aquariums. They have to have both, in dishes deep enough to submerge in.
4. Get rid of the pellets and commercial hermit crab food. They contain preservatives and ingredients that are toxic to the crabs. The Safe Food List is linked in the care guide posted earlier in this thread.
5. They are more than likely both Purple Pinchers but a photo would help make 100% sure.
6. Each crab needs 3-5 extra shells of the type they like and incrementally larger sizes. PP's like turbo, murex, and magpie shells (just a few). Turbos are always a good bet. You can find them at craft stores nowadays! Bags of green turbos are cheap at Michael's, JoAnn, etc.
7. Remember that anything that kills insects will kill crabs.
8. The crabs need several inches of substrate and once your tank is set up correctly you will not need to do anything other than remove moldy bits of old food. Beneficial bacteria builds up in the substrate and breaks down waste. Essentially you are creating a closed micro-ecosystem for your crabs.
9. That's great! As long as they can hook a leg over the side of the bowl they can get out. Bowls need to be deep enough for them to fully submerge
10. Again, please read the care guides thoroughly and chuck the desert sand.
11. Don't handle your crabs or bring them out of the tank. They view anything larger than them as a predator, especially from above. They're wild animals caught on beaches and the best thing to do is leave them alone and only handle them if necessary. The humidity and heat in your home is very likely too low (unless you live in a rain forest, lol) and the hightened activity is actually them panicking. They need several weeks to months to dig down in proper substrate, destress, and molt.
Here is another link to the care guide so please give them a read through and consider making the necessary changes. These guys can live for over 30 years in captivity so we want your crabs to have a long, healthy life.
http://www.hermitcrabassociation.com/ph ... hp?t=92457
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