Wood mold

[LoveTheEarth11]

I don't know if this subject is classified as emergency, but it could be long term? I have some spider wood that is part of my 'bioactive background' and It has started to seriously mold because of how high the humidity is (above 85). I have removed the removable pieces(stuff in the substrate and/or loosely on the ground), but this one is part of the bioactive background, so it is stuck to the glass by 'the great stuff' (expanding foam). I have looked into microfauna, like springtails, but people have told me they only eat 'mold spores' (Not what I have). I really do not know what to do here. Removing the hermit crabs from the tank is not an option, as I have no spare cage and the pet stores are closed due to COVID-19...

Can anybody help?

(To answer all the questions required to make this post::)
I am using a 50:50 eco earth to play sand mix. it is 9 inches deep
I have a zoomed temp and humidity gauges. It reads 75 F and 85 Humidity. (They are located at the top of the tank)
I have a huge zoomed heat mat on the SIDE of the tank. (Not underneath)
I have two water pools. one for salt, one for fresh. I use prime to dechlorinate it. It is fully cycled with running filters. (But these water pools are built-in with the aquarium. Its kinda like a paludarium design? its not removable.)
I feed fresh food, such as banana or kale, and grains such as oats or chia. for protein, I give cuttlebone and crushed eggshell. (It changes a lot. They also feed off of live plants (food is replaced every day))
I have had my PP's for about a year and a half.
1 crab went under (to molt) for the first time a few days ago.
They are in a 45 gallon, with a screen lid.
There are five hermit crabs, two large, one medium and two the size of a quarter.
Lots of extra shells. Like 15?
No chemicals/fumes.
I clean the tank at least every 4 months. by removing all substrates and washing it all down with white vinegar.
No, sponges are NOT used!
Nothing new added to the tank.
There is also some type of mites in the tank. I don't think they are affecting them molt though.

[Motörcrab]

I err on the side of being cautious with mold period. It is thought mold is not harmful to hermit crabs since they have gills. I personally tend to disagree with that belief with my hermits. Others will argue that mold is harmless to hermits. Molds are generally considered unsafe for humans since breathing in the spores can cause all kinds health of issues. I weigh my decision based on my health over the crabs. I remove all molds from the tank whenever I see it.

Based on my thoughts, since you can't remove the moldy wood without destroying the decorations you can try cleaning it. I would use a face mask and gloves while doing this because of the above mentioned risks. I would remove what decorations and food containers and water pools I can, even the crabs that are above ground while cleaning. I would use some warm, not hot, dechlorinated salt water mix and a toothbrush to scrub the mold off.

The saltwater helps to curb mold from growing on woods and other natural materials.

As for moving your crabs temporarily you can place them in a small plastic container with a little substrate from your tank while you do the cleaning for an hour or so.

[wodesorel]

Springtails should eat mould, I've never had an issue in tanks where they were present in high enough numbers.

I agree that scrubbing with saltwater should work. I boil all wood going into the crab tanks in heavily salted water to prevent any kind of unwanted growths due to the humidity. (Regular kosher salt, which is crab safe.)

[LoveTheEarth11]

I err on the side of being cautious with mold period. It is thought mold is not harmful to hermit crabs since they have gills. I personally tend to disagree with that belief with my hermits. Others will argue that mold is harmless to hermits. Molds are generally considered unsafe for humans since breathing in the spores can cause all kinds health of issues. I weigh my decision based on my health over the crabs. I remove all molds from the tank whenever I see it.

Based on my thoughts, since you can't remove the moldy wood without destroying the decorations you can try cleaning it. I would use a face mask and gloves while doing this because of the above mentioned risks. I would remove what decorations and food containers and water pools I can, even the crabs that are above ground while cleaning. I would use some warm, not hot, dechlorinated salt water mix and a toothbrush to scrub the mold off.

The saltwater helps to curb mold from growing on woods and other natural materials.

As for moving your crabs temporarily you can place them in a small plastic container with a little substrate from your tank while you do the cleaning for an hour or so.

Yes, I totally agree with your train of thought. Mold does seem to irritate my crabs, just as it would if it were me. I don't like seeing my crabs 'suffer' even if others say they are not.

As for using salt water to kill the mold, I realize how dumb I was to forget that. As not too long ago, I pored saltwater in the soil to get rid of mites. I don't see why it wouldn't work on mold as well.

Thank you for the helpful information! I was seriously panicking that I would have to destroy the entire background, or risk my crabs getting sick.

[LoveTheEarth11]

Update:
I scrubbed all the wood in a very strong saltwater mix. It has been a few days and there is absolutely no signs of mold! my crabs look a lot happier and healthy now. I think it's gone for good.

Thanks to everybody who replied. Your comments and tips have been a great help.
Thanks =)

[gflor119]

I don't have wood mold, but my tank is developing mold in the substrate, around the dishes, and a little on the tank walls, I also noticed a tiny plant growing from the substrate!!! Any ideas as to how to prevent mold? I've read up on using saltwater to mist instead, but I'm getting mixed opinions on it.
Substrate: Eco Earth, at a 1-2 to 6 inch incline
2 hermies (Zoidberg and Hermes)
20 gallon tank
Proper diet,temp, and water
As for the wood problem, I've heard that people use the bake or boil method to kill bacteria and when you clean the tank clean everything naturally and in depth
Thank you and I appreciate any advice/help!!!

[Motörcrab]

If you can post some pictures it will help us see your issues and give you a better assessment of your set up.

In the meantime here's what I can determine from your post.
Is the mold in the substrate or on the surface?

With it being around the food dishes it could be from food they carried out of the dish. If that's the case you can just spot clean buy pulling the moldy stuff out. Sometimes Eco Earth stuck to the walls will look like mold. Mold can also grow if you get a lot of condensation on the inside of the tank.

The plants growing are probably just from seeds they the crabs planted. They are harmless and the crabs will probably eat them.

Having only Eco Earth as your substrate increases your chance of mold since it is organic plant matter and will break down.

Trying to add dechlorinated salt water to your substrate after the fact is risky. You can over saturate your substrate and cause a flood. Introducing too much salt to the substrate can be dangerous. It could potentially cause chemical burns if too strong. I wouldn't recommend trying to add it to your substrate unless you are mixing new sub.

Redrying your substrate either in an oven or spreading it out in the sun for a few hours should kill any bacteria and dry it out. I personally like to just replace the substrate for the peace of mind and time it takes to dry it.

Boiling things in saltwater is usually for items like netting or pieces of wood that have molded. When everything is wet and hot you need to scrub the mold off.

I would recommend making your substrate 6" across the entire tank. It will give your two crabs more space for molting. I would also purchase at least one 50 pound bag of playsand from a home improvement store and add in Eco Earth. 5 parts sand to 1 part Eco Earth is what is recommended. Honestly it can be mixed to any ratio you like. The 5:1 mix is what is closest resembles beach sand. It is really just a personal preference. While mixing the substrate is when you can add dechlorinated salt water to the mix. After the tank is up and running if you need to occasionally mist with dechlorinated fresh water.

[wodesorel]

You can spray the surface with saltwater a few times which will add in salinity without overwetting. Since you're just seeing surface mould it should help control it.

[gflor119]

Thank you both so much! It was just on the surface and I did clean it out so there isn't any to take a picture of right now, but I'll look into some playsand and I might change the whole layout of the tank and make it 6 in. all around. Thank you!