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Cycling a hermit crab tank? (long post)

Discussion in 'Discussions, Theories and Trial Ideas' started by kcgirl81, May 31, 2007.

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  1. kcgirl81

    kcgirl81 "Never Molted"

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    Hello all,
    I have been a member here for a good while, but don’t post much so you may not recognize me. I flit around to various hermit crab sites to see what’s going on in the crabbing world, and recently I came across a theory that puzzled and intrigued me. I think you all are some of the most knowledgeable and experienced crabbers I know, so I wanted to run it by you.

    The idea is that it might be possible for a hermit crab tank to be “cycled” in a manner similar to a fish aquarium, thereby eliminating the need for deep cleans, which stress the crabs, sometimes resulting in disturbed molters or dropped limbs. By seeding the soil with certain beneficial bacteria, you would in effect create a filter out of the entire substrate, so that wastes and uneaten food would be broken down into harmless elements. The tank would house plants as well, which would utilize the now harmless “fertilizer” in the soil. In this paradigm, you would do daily checks and weekly partial substrate changes. You would use a soil tester to determine the condition of the substrate. Basically, the crab tank would become a full fledged terrarium. This is all based off of the aquarium paradigm, where a tank must be cycled before being safe to house fish. Once the cycle is complete, the wastes that the fish produce are broken down by the bacteria which live primarily in the filter, and which neutralize the toxic substances.

    This idea, if possible, would have several positive benefits:
    1. Crabs would not be unnecessarily stressed.
    2. Molters would not be disturbed accidentally.
    3. There would be less worry about buried pieces of food creating mold or other problems.
    4. The environment would be as natural as possible.

    There would also be some cons, however:
    1. It would be a lot more work for the crab owner, since the habitat would require daily substrate maintenance.
    2. Dead crabs might not be discovered, and the overdose of toxins in the soil as they decayed might crash the system.
    3. It would be much more difficult for the crabs to be cared for while you’re on vacation.

    I’m sure there are others, both pros and cons, that would come to light upon further study.

    My thoughts on this are divided. First, I don’t think that the comparison to an aquarium cycle is valid. I have been a crab keeper for about two years, and an aquarium keeper much longer, and I don’t see much of a similarity between the two habitats. For one, fish don’t live in their filter. The filter holds all the gunk and debris so that it is kept out of the fish’s living space. In the crabitat, the substrate is the main area of crab habitation. They spend much of their time buried or digging, and I’m not sure it would be healthy for them to be living in their “filter.” Second, the bacteria in a fish tank live primarily in the filter and on the surfaces, not in the water which the fish breathe. Of course, crabs don’t breathe their substrate, but still they spend most of their living time there. Third, we know a lot about the exact toxins which are present in a fish tank—primarily ammonia from fish waste and uneaten food; we know exactly which bacteria break this ammonia down and produce the nitrite by product, and we know which bacteria break down the nitrites and produce the nitrates. We don’t know anything nearly this specific for soil based systems. Fourth, in an aquarium, the entire substrate can be vacuumed weekly to remove uneaten food and solid waste—this is not possible in a crab tank. The partial substrate change does not equal a partial water change, because all of the substrate that is left still has the solid waste decaying in it.

    However, I know there are folks out there who are much more knowledgeable than I about this whole terrarium concept. If this is possible, it might be worth experimenting with. Personally, I’ve only had one crab ever drop a limb during a deep clean, but if this procedure could have saved that one crab from being stressed, would it be worth it? That crab today is happy and healthy and suffered no long term effects. However, folks who have a lot more crabs than I do might find it impossible to do deep cleans without disturbing a molter.

    That’s why I wanted to bring this idea to the attention of all you dedicated crabbers. I’d love to hear some discussion on this topic. If any of you have had experience in this area, or can offer any insight, I’d love to hear it.

    Thanks for taking the time to read!

    Susan
     
  2. starmaiden

    starmaiden "Preparing For Fourth Molt"

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    I think it was Cisgarna (sp?) on the HCA that first proposed this concept. And I think Thalia is building an actual vivarium, complete with worms even to process the soil. Jedediah has mentioned that she hasn't done a deep clean of her crab tanks in a long time, I think she said something like two years, because she preferred to use natural means to keep it clean like beneficial insects and bacteria to break down the waste matter. For large, sparsely populated tanks, I could see that system working.

    With my tanks, I find that most of the waste material collects on the surface, so I do frequent spot cleaning. And I usually let my tanks go for 4 to 6 months between deep cleans. Since trying the beneficial mites, I found I like having them and plan to add beneficial mites with each deep clean from now on. Not only do they eat the bad mites, but they eat fungus, poop, and bits of leftover food as well, so they are good little tank cleaners to keep around.
     
  3. CrabbyChris22

    CrabbyChris22 Hi, I'm New Here!

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    hi susan,

    jedithrashermaster i think posted a couple of weeks ago in this thread about partial deep cleans. apparently he doesn't replace 100% of the substrate either.

    i wanted to address something you said in your 6th paragraph. in captivity and in marine aquariums, fish DO indeed live in their filter in the case of live rock aquariums; they also live w/ the micro-organisms and bacterias too. i'm not an expert at all on that subject but i'd done some studying on it because i REALLY want to have a big ole marine aquarium w/ live rock.

    as far as partial substrate changes; i don't see too much wrong w/ that and would be willing to try it too. if you were to take say the top 2-3 inches out and then replace that while mixing the new in w/ the old (actually turning it to get it throughout) you would be able to locate molters as well as a possible dead crab. besides, you want to moisten the substrate all the way down.

    i may have to give this a whirl. i've thought about it but now as the subject keeps coming up it may be worth a shot. i like the beneficial mite idea that starmaiden wrote about too. i might think about getting some. let nature do the work...
     
  4. vckums

    vckums Moderator

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    There's a thread over on CSJ about this topic. I wanna saw the Debateable section but I could be off. People who chimed in had alot to say and it was a really good thread. I think the main problem was the expense and time this would take.
    I've never had a crab drop a limb when I did a deep clean. I do mine every 4-6 months. I wet part of my substrate and the rest wicks out. Personally I hate bugs and couldn't have a tank with them, but it's a personal preference with me. :chuckle:
     
  5. kcgirl81

    kcgirl81 "Never Molted"

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    Ditto. I personally have never seen any ill effects from doing a deep clean (except for that one dropped leg I mentioned before, which could have been for other reasons), and I just feel better knowing that all the gunk has been removed. I know others have had different experiences though.

    About the filter thing—I don’t know much about marine tanks as I have always kept freshwater myself, but what I was referring to (and I should have been more specific)was the mechanical filter that keeps all the gunk from floating around the tank. In other words, the solid waste is much more easily removed from an aquarium than from a terrarium substrate. It’s true that the microorganisms inhabit nearly every surface in the tank.

    I guess what I’m really saying here is that the terrarium idea is a good one for those who have the time and resources (and desire) to do it. But for the average crab keeper who just wants to keep pets, I think the deep clean method is still sufficient, as long as it is done in such a way as to minimize the stress to the crabs.
     
  6. vckums

    vckums Moderator

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    I know Julia Crab uses a drainage system in her tank. I helped her deep clean it last time and it was amazing! I'll see if she's got pics of how she set it up still.
     
  7. shmama

    shmama Guest

    :vinkko: Where would I find out about & possibly where to get the beneficial mites??? - interesting! :froggz:
     
  8. vckums

    vckums Moderator

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  9. shmama

    shmama Guest

    :thanks: Vicki~ :rockz:
     
  10. vckums

    vckums Moderator

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    :airkiss:
     
  11. kcgirl81

    kcgirl81 "Never Molted"

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    Vicki, I'd love to see pics of Julia's set up. Sounds great. By the way, I love your sig--great movie!
     
  12. vckums

    vckums Moderator

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    I sent off a message to her about the pics. So Im hoping she has them still. Thanks, I think that's my favorite part of the movie :yes2:
     
  13. vckums

    vckums Moderator

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    I know she used some plastic grid for the bottom of the tank. Cut to fit the tank. Then there was lava rock used and them some other brown round ball thing, can't recall what it is. I'll ask about that part. Then she put some black garden cloth over the top of everthing and then put the sand onto that. Any water drained to the bottom and evaporated. There was a tiny amount of water in there, like 2 tablespoons and the tank is a 65g like mine.
     
  14. Crabaddict

    Crabaddict Guest

    Wow, Keri's method is very interesting. She barely adds water to her sand, which is smart 'cause the crabs can make it pretty wet sometimes. My question is do the crabs rip the garden cloth when they dig under for molting? Not that it would be bad but it would defeat the purpose of the drainage system if sand mixed at the bottom where water would settle. I'd really like to see her pics.
     
  15. vckums

    vckums Moderator

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    When we did the deep clean some were able to dig under and get to the cloth. But there wasn't real big holes and no sand was at the bottom.
     
  16. crystyle

    crystyle Guest

    For those of you who have experience with using beneficial bugs how do you know how many bugs to use in what size tank?
     
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