Time to reinvestigate sand/EE - new active/cycled substrate

This is where you discuss the conditions of your crabitat -- temperature, humidity, substrate, decorating, etc.
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Time to reinvestigate sand/EE - new active/cycled substrate

Post by JediMasterThrash » Sun Jan 28, 2007 10:13 pm

I just read the Deep Clean thread in this forum. This is a thread I made on LHC. There's definitely some overlap with this thread and the deep clean thread, but the focus on this thread is in the types of substrate themselves, rather than on how often to change/clean them.


The problem is that both coco-fiber based substrates and sand are initially sterile. Also, some people have issues with sand being silica-based (possible dangers if regularly inhaled by human lungs, though this isn't an issue for crabs).

Bacteria and microbes form when the substrate is moist, and these readily break down poo and discarded food. So I've assumed these are beneficial in the past. However, I really have no idea how to measure their levels. Also, as they break down poo, they likely release ammonia. How are those levels?

Also, what is the pH of the soil, and what should it be? Cocofiber lowers pH, while lime or calcium-based sand increases pH.

I think the answer lies down one of two paths:

1. Creating a proper "Beach" substrate.
2. Creating a proper "marsh/jungle" substrate.

The idea is that we should create active substrates with a proper mix of bacteria, microbes, bugs, etc, to keep everything in balance. We probably need to start out with an infusion of small amount of natural balanced substrate, either active reef substrate, or natural leaes/litter from clean wooded areas.

Then we need a substrate which will become naturally cycled and maintain this balance.

If successful, we should have healthier crabitats that can go for years without a deepclean, and should be healthier for digging, molting crabs.

1. For a proper beach substrate, I assume something made for reef-tanks would be appropriate. Like aragonite. There was also a thread on CSJ about micro-sized gravel (apparently what Carol of Crabworks and her 37 year old crabs use), though it looks like it's not available anymore.

2. For a proper moist jungle substrate, I found this site for amphibian vivariums:
http://www.livingunderworld.org/amphibi ... 0021.shtml

It recommends using decaying leaf litter or activated substrate from an aquarium or natural pond to introduce a colony of beneficial bacteria. Bark or coconut husk chunks in the soil can help with aeration.

Most of what I've read says to keep the soil well moist to keep the beneficial bacteria colonies to decompose surface matter. If matter isn't properly decomposed, it can become toxic.

It needs aeration because anaerobic bacteria can be harmful. This page seems to indicate that having larger chunks of matte in the substrate helps with aeration. Probably because they help trap air pockets, and help push stuff around more when they dig in it. With the amount of tunneling and digging that hermit crabs do, I'm not sure I'm too worried about aeration.

I want to experiment with a natural substrate in my next crabitat iteration in a few months. So I need all the input and suggestions I can get. And also to find on-line places I can order everything. Is there anywhere on-line you can order safe leaf-litter?

Here's one recipe that might be worth trying:
2 parts inert sand.
1 part ground coconut husk fiber (expanded, see below).
1/4 - 1/2 part fully composted leaf litter.
1-2 cups of substrate from an established aquarium or natural pond.

http://www.livingunderworld.org/amphibi ... 0020.shtml

It suggests ammonia buildup only happens in pooling water. So you need to avoid oversaturating the substrate such that water can start to collect at the bottom. It's probably best to get the sand moist at the start, and then only add water or mist as necessary to keep it moist and the humidity right, but not too much as to oversaturate it.

It also reiterates that sterile substrates can be harmful to animals because there are no beneficial bacteria to break down matter or overwhelm harmful bacteria. I think it's very important that we somehow find an easy way to create a cycled substrate for hermit crabs.


For a while several months ago, I had been suggesting that we should recycle some of our substrate during a deep clean to re-use as-is in our new tank to infuse what beneficial bacteria/microbe colonies existed in the previous tank. (i.e., don't bake it).

However, Sue from Coenobita Research thought that my above statement, as well as using dirt or compost, were potentially bad ideas for a variety of reasons, some of which (But not all) seem to not have the same concerns/warnings as the website I linked above.

Sue's arguments were (pardon me of I incorrectly represent something, but I'll do my best) that we have no way of knowing what the bacteria colonies are, and the ratio of beneficial to lethal. Baking the substrate would kill off most, but not all, which might keep it in check (but to mee seems like it might defeat the purpose). Also, proper fluctuations of heat, light, and humidity promote bacteria diversity. Without this diversity, there's no way to ensure that we keep the bad bacteria in check. Soil/compost isn't good because it's in a constant source of decay, and we can't control it well enough in our small environments.

My crabitat has naturally had diversity, expecially with my latest iteration. I have timed UV lights for day/night fluctionations, and timed bonus 50w moon-glos to provide temp and humidity daily fluctuations to more closely model real life. I have good air cirulation with two tropicaire humidifiers. And I'm not worried about substrate aeration due to the contant digging and tunneling of the crabs.

Also, by having mostly inert substrates such as sand or coco-fiber, and only a small amount of compost, would this keep any decaying process from the compost in check?

There's also one other catch. What do we recommend for smaller, newbie crabitats? Assuming they have more trouble with keeping temp and humidity in check, and might not have any air circulation or day/night cycles, what is best?

1. A sterile substrate that grows "hopefully beneficial" colonies in moisture. This is currently what I and most crabbers are doing. It breaks down matter extremely well, and theres good success with molting. However, I still feel I could be doing better, as my crab half-lives are still in the 2-5 year span, and I'd much rather have 20-30 years.

2. A sterile but dry substrate (Sue also said that dry bacteria are usually safer). But I haven't found dry substrate to be effective at all in breaking down matter, and the website above said that old matter can become toxic if not broken down. Also, our crabs molt better in mosit substrate, and moist substrate is necessary to keep the humidity up. So unless you micromanage your crabs, I don't see how a dry terrarium can work.

3. Active/cycled substrate, which potentially requires day/night cycles and aeration to work properly. How well can we create a safe and easy active substrate recipe for the general crabber?

While I'm on the subject, I was also looking at water, and was wondering if there's any benefic to adding some aquarium chemicals to balance pH and ammonia to larger water pools?


My last thought is whether you'd have any issues with the bugs getting out of the crabitat and into the house/other pets/house plants, etc?

That's the only thing my wife has against me trying this out. She's afraid all the bugs will escape and create troubles in the house.

There was one time I had flies breeding in the tank, and that didn't go over well...

Stuck-up, half-witted, scruffy-looking crab-herder since '92.


Post by Guest » Sun Jan 28, 2007 10:35 pm

I know there has been a lot of back and forth on this, and I have toyed with the idea of a virarium tat, and had come acrossed this website as well.

I do agree that this is an area that can be improved apon, and if we can get this down to a science then I feel we may very well have many less terminal molts. Cisnegra is absolutly onto something I think, but we have to I feel 1#be able to explain this in a way that every crabber can easily grasp the importance of it, (I mean, as a layperson and a non fish person so much of this took me multiple reads and looking up words to understand what I was reading-I'm sure I'm no the only one-I actually think the above post does put it pretty suscintly) and #2 get it down to a science so other crabbers can duplicate it, and #3 make it as easy as possible for other crabbers to duplicate, for example to have a step by step guidline on the bare minimum requriments to make this viraruim tat sucessful for 10-40 gallon tat and then for a 40 gallon and up.

There are several things I'm taking away from these discussions that would be easy for me to do, for example a soil kit cost around 15 bucks to test the spoil, but I really don't have the confidence that I know what I'm testing for, I'm guessing the kit will indicate on it when a soil is to a toxic level.....Also adding a couple of plants and breaking out the humifiders is something easy I could do (realivily that is-I kill plants, hopefully I could keep them alive for the month they need in order to leak out the nasties into the soil). But I really feel like I'm shooting in the dark here.

Those with the expertise need not only to test this but they should try and make it easy for the average crabber. There is no way I could make what cisnegra has in her tat, I do not have the tools, many of us don't have those resources. I can't stress enough, for this to be well received it must be easy as possible, or it will never go anywhere.


Post by Guest » Mon Jan 29, 2007 12:34 pm

Crabber, I agree with you 100% on this one, and I think that's what I took away from the discussion in the other thread. While it's true that making the 'tat environment as close to nature as possible would be beneficial, if it requires huge amounts of research and money, the average crabber is not going to do it. And for that reason, I think it can be dangerous to advocate this method unless you give detailed specifics on the how to. Otherwise someone might read these threads and say, "oh, if I add a plant, I never have to deep clean again." There goes the crabitat.

I hope we as a crabbing community can work this out, because I for one am eager to try some of these suggestions as well. But I'm not totally convinced that we can do away with the deep clean completely. Soil qualities and decomposition rates are just too unpredictable to trust that there is nothing nasty going on in the substrate.


Post by Guest » Mon Jan 29, 2007 3:05 pm

Just another practically issue, what if I test my soil and it's at toxic levels, how do I fix the problem? Right now I don't have a clue.

I know I'm just repeating myself here, but I'm doing so because I am very intrigued by this idea and would so much like to adopt it, but I hope those who are using and testing this method are doing so with considerations not only for their own tats, but for the crabbing community as a whole. I think it could benefit many, many crabs out there.