New Tank Design

celticstarb · Post by **celticstarb** » Sat Jan 31, 2015 9:26 pm

This is my first post here. Currently I have 2 PP in a 10 gallon. I want to upgrade their tank and get them some more friends. I have a 100 gallon aquarium that has been empty for a long time, and decided that it would make a great home for my crabs. I am thinking of making a pond on each end of the tank. I plan on using 10 gallon aquariums with ramps to make the ponds. One pond will be fresh water and the other saltwater. I was hoping to make each pond a fully functional aquarium with filters. This would mean I would have a 12 inch deep substrate layer. I was thinking on heating it with Flex Watt Heat Tape and a temp controller. The temp probe Would be buried about under the substrate about 2 inches from the bottom to make sure the substrate doesn't overheat. I am not sure if the heated substrate would be enough to heat the whole tank, but I can always add heat lamps if not. I will also add aquarium heaters to each pond, so that will help heat the tank as well. For decorations, I was thinking of adding edible plants like marigolds and lettuce, grown from seeds. I will also add lots of driftwood for climbing. Can anyone think of ways I can improve this design, or possible something I should do differently? Do you think the ponds will be too deep even tho they will have ramps to get out if needed?

Geranium · Post by **Geranium** » Sat Jan 31, 2015 11:46 pm

It sounds like you're heating from the bottom, is that correct?

Thea · Post by **Thea** » Sun Feb 01, 2015 2:48 am

I would love to see this when complete. Tx

Crabber85 · Post by **Crabber85** » Sun Feb 01, 2015 4:39 am

Your tank design sounds fascinating but your heating method is actually dangerous for the crabs any heat applied to the tank should never start from the bottom as the substrate acts as an insulating barrier trapping the heat the heat will build up and since hermitcrabs don't feel heat the way we do they will cook themselves before they realize they are in danger, I have all of my crabs in a 120 gallon tank and have done the pool ideas using smaller aquariums complete with filtration and it did not last long unfortunately.Putting electrical cords where the crabs can reach them is only inviting them to taste test the cord which means they will nip the cords exposing the wires underneath which will only lead to the crabs or you getting electrocuted, the other issue with filtration is the fact that hermitcrabs drag in a ton of substrate with them when the enter the water and this substrate whether it be sand or coconut fiber ends up gunking up the filters which will eventually burn them out and believe me I speak from experience.lolYour best bet for filtering the water is to use a submersible unit meant for filtering dirty turtle water as these units are designed to handle a much heavier waste load they will work far longer.I've found that heating a tank over forty gallons requires a combination of side or back mounted heat pads and an overhead heat source such as a sixty watt infrared heat bulb.I have two heating pads mounted on the walls of my tank so that they meet at the right back corner and then the heat lamp is positioned on the screen lid above that this creates the desired hot spot and then the heat just gradually works it way out to the far left side dropping a degree or two every six inches away from the hot spot so that I have at least three isolated temp zones for my crabs to choose from this is the ideal way of heating a hermitcrab enclosure as it gives them the choice depending on their current needs.

celticstarb · Post by **celticstarb** » Sun Feb 01, 2015 4:54 am

I think I will have to heat from both above and below. I always use thermostats with heating equipment. I raise reptiles and have learned to never trust heating without temp controls. I'm just worried that, with a 12 inch deep substrate, it will be too cold for molting (my house gets pretty cold). This way I can better control the substrate temp. I am still trying to decide if I want to use ceramic heat emitters or incandescent lights for heating above ground. Using lights would require an extra timer. I also thought about Flex Watt heat tape along the back, but I really want to have a coconut fiber background for looks and to add climbing space, and that would insulate the back glass.

Crabber85 · Post by **Crabber85** » Sun Feb 01, 2015 5:24 am

You don't want to heat the substrate directly only the air above, hermitcrabs burrow down in the heat of the day to get away from the heat because the further down they go the cooler it gets so it would be counterintuitive to put a heat source where one doesn't exist naturally.When a hermitcrab creates a molt pocket the temp and humidity are completely stabilized in that pocket this is the primary reason why hermitcrabs will burrow down and stay underground in these pockets when surface conditions are unfavorable because these pockets create little micro-climates that don't vary much if at all so heating the substrate is not needed.I've never heated my substrate in the last twenty something years of my keeping crabs and never had a problem with the substrate being too cold, molts are not so much effected by substrate temperature as they are by diet, light, space and shell availability.I know some crabbers who have heated their substrates because they felt like the sub temp was just too cold ie below sixty degrees which is admittedly chilly but in all reality hermitcrabs are cold blooded they are exothermic they can only control their body temp with the aid of an exterior source and much like fish don't really get cold so much as get sluggish a drop in temp will only slow them down though this can turn into a serious issue if surface temps are below seventy-five for long periods of them the temporary sluggishness will turn into a permanent shutdown of vital organs which will end the crabs life prematurely.If you can control the heat output like another member of ours who is using gentle under tank radiant heat from a heat source he built himself then you can fine tune the temp of the sub without risking overheating or baking burrowed/molting crabs, uth pads don't allow for this degree of control being that they have no adjustable temp scale they only put out at one temp which is dangerous as I'm sure you know.Ceramic heat emitters are a good alternative if you don't want any light broadcast during the night which some crabbers don't but I've found the the infrared heat bulbs do the trick and are a little cheaper though the warm red glow they give off does take some time to get used to since I have my tank next to my bed.lolOnce you completed your setup please keep us updated as I'm eager to know how your under tank heating method works in comparison to a radiant heat source built right into the top of the stand this is the other idea thats being used and so far its been a success.

celticstarb · Post by **celticstarb** » Sun Feb 01, 2015 8:50 am

Thanks for the ideas. I have revised my plans, again. I think I will only heat a small area under the tank. Maybe a 5" X 5" area, heated to 75 degrees. This should allow the crabs to choose the temp they like best in the substrate. I am trying to iron out all the details before I start the build since this aquarium is huge and changing things later will be a real pain.How about the ponds? Is it ok to use a pond that deep, as long as there is a safe way for them to climb out? I know the idea of fully functional aquariums as ponds will slow the build since I will have to cycle both aquariums, but I think the filtered water would be beneficial. I want to create as close to a natural environment as possible.

Crabber85 · Post by **Crabber85** » Sun Feb 01, 2015 9:08 am

Your welcome for the ideas and info and yes the pond idea is actually one that is doable in such a large enclosure which will give you a better chance at creating a long term stable environment for the crabs.You can definitely do pools that deep as long as they have a way out that easy to use they'll be fine and again I speak from experience though I just used a couple of five gallon acrylic aquariums.Doing a filtered pond setup with at least five gallons of water is going to make so that you only have to completely replace the water once every couple of months which is ideal and puts less stress on the crabs.Use some crushed coral as a bottom layer and it will help to calcify the water which will be an additional calcium source for your crabs to draw from, I did this with mine and still use pieces of coral in my smaller water dishes and have noticed a dramatic improvement in their overall exo-skeletal health, multiple sources of calcium in the enclosure will ensure that the crabs maintain good skeletal density which means less injury risk to the limbs from short falls and an overall healthier crab.Some species of hermitcrabs wont bathe on their own because they have a natural fear of water but the Purple Pincher and the Ecuadorian the two most commonly available species here in the US do readily bathe on their own and prefer to do it themselves rather than us force bathing them outside the enclosure so your pool idea is again ideal for this reason alone.I do have caution that the filtration units depending on which type you chose should be covered in a way that will keep the crabs from getting inside them at any point including where the filter pads are placed as this can be a quick death sentence for the crab.As far as heating the substrate if you want to just heat a smaller area thats fine as well just as long as you can keep the temp controlled there shouldn't be much of an issue.

celticstarb · Post by **celticstarb** » Mon Feb 02, 2015 6:56 am

Thanks. I plan to use aragonite instead of crushed coral since it has less of an environmental impact. It's the same principle tho, adding calcium and buffering the water.I think I will use red heat lamps, since the new tank will be in the hallway. These will also let me see them in action at night, albeit not very clearly.Has anyone set up a tank that mirrors seasonal changes? For instance, slightly shorter photo periods during the winter? I do this with many of my reptiles, and it greatly increases overall health and well being.

Crabber85 · Post by **Crabber85** » Mon Feb 02, 2015 7:31 am

Being that nearly every species of hermitcrabs come from a tropical region close to or on the equator they don't experience the shortened days of our winter so we have to give them as close to a twelve hour day night lighting cycle possible to keep them eating and to help them maintain a regular molt schedule.Hermitcrabs are very dependent on the lunar cycle, they use this to keep their internal calender fixed so that they molt on a repetitive schedule.Hermitcrabs just like most reptiles see in the Ultra-Violet range of the light spectrum so using black light bulbs for night time heating actually confuses them because this kind of light bulb is made to filter out everything but UV light which gives that odd glow the crabs see it as being day time all the time which impacts molt patterns and even basic nightly habits like eating because they are nocturnal in large part.Your main light source for daylight lighting needs to be UV-B this is to stimulate their natural vitamin-b production and is absolutely necessary to keeping them healthy.We like the Repti-sun UV-B 5.0 and 6.0 lights as they last a while and a little cheaper than the other brands out there.

celticstarb · Post by **celticstarb** » Wed Feb 04, 2015 1:58 pm

I was curious about purple pincers that are commonly found in Southern Florida. Southern Florida has pototoperiods from 10 to 11 hours during the winter. The average temp drops to the upper 60's and lower 70's. I would never go below 78 degrees, but that is a drop from the 82 degree areas of my crab tanks. Just curious if anyone has tried it? I am not planning on trying this unless anyone has tried it and found it beneficial. And even if someone found it beneficial, I would still offer them a hot spot of 82 degrees so they can thermoregulate if needed. I 100% agree that they are far more dependent on lunar cycles. It just makes sense. Most marine animals breed during the full moon when the tide is highest, thus insuring better disbursement of their eggs. Also, the increase in zooplankton during the full moon allows for a higher percent of each species to survive until hatching.Thank you, Crabber85 for all your help. You are a very interesting person to talk to, and full of helpful knowledge. I really appreciate the help and patience you have for the others on this site.

Crabber85 · Post by **Crabber85** » Thu Feb 05, 2015 6:22 am

Your more than welcome its why I was brought on as an admin so I wouldn't be doing my job if I didn't offer some friendly info and help.I believe Tammy and Kirk the lovely couple who and run the hermitcrab patch.com have done great strides in finding out about the Purple Pincher which they used to sell but don't anymore and they brought to us a lot of new information one of which was that the crabs did better with a full 12 hour day night light cycle when in captivity not sure why yet.I've personally never been able to do a full 12 hour day night light cycle so I try to do as close to that as possible typically ten hours of light followed by approximately fourteen hours of dark and this hasn't seemed to hurt them any.We typically try to encourage our members to shoot for a day night cycle as close to the twelve/twelve as possible given their limitations as not all of us have timers for our lights and things we have to try to do things manually as close as possible.By all means test out a shorter photo-period and let us know what the results are as unfortunate as it is trial and error and safe experimentation are the only ways we have been able to get the info on them we now have today if it were not for member like you who want to know something we currently don't we wouldn't be here today.

celticstarb · Post by **celticstarb** » Thu Feb 05, 2015 11:37 am

What about safe wood? I can't find a list of which woods are safe. I did find a list of woods to avoid. I was wondering if Oak wood would be ok? I had to cut down an oak tree that was struck down during a recent storm. It has many nice branches that would make great climbs for the crabs. I know oak leaves and bark are considered safe, but what about the wood itself?

Laurie LeAnn · Post by **Laurie LeAnn** » Thu Feb 05, 2015 4:03 pm

You will want to soak in their salt water for several days to kill anything and then bake it dry on low heat. If you don't do this you run the risk of getting bugs in your tank that you didn't know we're in wood! I know, been there.. done that! I didn't soak mine long enough and just air dried and I stuck it my tank and with in 4 days I had little creature things all over and it was very hard to get rid of..I think I did a couple tank cleanings i mean full blown cleanings before I rid of them

Crabber85 · Post by **Crabber85** » Fri Feb 06, 2015 3:05 am

Oak is safe as long as its a tree that has never been treated before and has sat on untreated land.If anything like fertilizers get applied to the ground they migrate all over via the water table and end up in the all the plants and trees on the property which makes anything grown on the property potentially toxic for the crabs.Red Maple is a big no no as are lucky bamboo and any coniferous tree like pine/cedar.You can use Cholla(pronounced Choya)and mopani(grape vine) as well.