HCA: Hermit Crab Association

I have heard that if your crabs tunnel, the tunnels can hold moisture and start to grow mold. I know I should replace the substrate three times a year and should scoop out old food and poop at least once a week.

I just want to prevent mold in the tunnels. I don't want to collapse them because one of my crabs loves tunneling and he may be in one somewhere.

My humidity is currently at 70% on one side and 80% on the other. Temperature is between 75 and 80 degrees Fahrenheit. The substrate is a mix of play sand and eco earth and it is between 5 to 6 inches deep.

I don't see any signs of mold currently, but I would rather take steps to prevent it than to fix it when it's too late.

Hello! I have never heard of that. I also have never replaced my substrate. I do sometimes work new substrate in, but that is once a year.

I personally have my humidity up to 99%. My temperature ranges from 79 (low at night) to 85 (hight during the day).

Mold doesn't hurt the crabs. It can harm us if we breath it in.

I’ve let my substrate sit for years without any problems. I’ve only ever had mold in the tunnels once, after a poor crab died and decomposed down there.

With multiple hermit crabs having different molting cycles, remixing or replacing substrate is rarely a practical option for me.

Mold won’t be an issue. Just spot clean the surface when needed.

I have had my crabs for 7 1/2 years, and have never replaced the substrate, just added new and mixed it in.

Thanks, everyone! You've all been super helpful

I have had my tank set up for over two years, and transitioning sizes with the same substrate, without any issues. You don’t need to remove substatte very often, just scrape the top layer for poop and leftover food.

What new substrate do you add mines is sand and the coconut stuff ... for humidity ... can I just mix in more of both when ever .....

And the smell of the cage like gets strong cause of the humidity is that normal and probably healthy !!?
Cause it is so humid or whatever

Most people use a 5:1 ratio of sand and eco earth. If you don't have crabs down you can add sub freely, if you have some down you can safely add up to an inch a day, just don't pack it down.