HCA: Hermit Crab Association

Hello all! I am preparing to set up my first tank and I had a question about other items mixed in substrate other than sand or ee. I am planning on mixing sand and ee somewhere between 5:1 and 50/50, as I am in an arid climate that sees cold winters and hot summers. I am hoping a bit more of ee will help with my humidity.

I was curious about anything else that should go in the mixture. I have seen that some people mix crushed oyster shell in, if I do how much would be needed for a 29g crabitat with around 9" of substrate?

I have also seen some mention of leaf litter or moss mixed in. Are there any other items I should consider mixing in?

Right now I am just planning on sand, ee, and some crushed oyster sprinkled in.


Thank you so much for all the information and advice available on these forums! It makes it so much nicer to learn more about these interesting creatures!

Welcome! I just caught your post before logging off for the night. HCA recommends playsand & eco earth mixture. 5:1 ratio. The leaf litter is added to the top of the substrate. So is the moss pit. The moss pit will need to be kept moist. I personally give oystershell as a supplement. I have heard a company adds it to their sand mixture. To each's own.


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i couldnt agree more with butterflies! i do a 2:1 ee to sand mix. helps alot with my humidity. im upgrading soon and plan to do more ee than sand. i also just off calcium in multiple sources for them to eat and munch on. just not sure how i feel about adding oyster shell. im sure it would be fine if you wanted to tho. i think my issue is i had a calcium sand scare so am just happier with it were i can monitor it easily.

I mixed oyster shell with the top 1/4 of my sub. I didn't use much. It isnt very noticable, but i know its there if a tunneler is craving a quick calcium fix. I just sprinkled it in as i was mixing, so i couldnt say how much. My tank is a lot smaller than yours. I also periodically sprinkle a little on the sub, as I noticed that it disappears.

Sounds like you've already got some sound answers Moss pits are used for the moss - the hermies like to hang out in it, eat some of it, etc. And u can spritz it with FW (fresh dechlorinated water) when the humidity starts to waver a bit. On top of my sub, I have sprinkled leaf litter, crushed oyster shells and crushed egg shells for the hermies and our isopods. You really don't need very much - a little will go a long way I would estimate for my 55g tank I sprinkled half a tsp of each. And u can add as much leaf litter as u like. Another good and fun thing to sprinkle in are some organic chia seeds! Some will get eaten and some will sprout adding a bit of color to the tat:D


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Oh and I also have regular oyster shells found on the beach and washed in the tank - the hermies use them to as stairs to get in and out of the pools. I'm pretty sure they have also been munching on it


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