HCA: Hermit Crab Association

Hi everyone! I'm new to this forum but not new to hermit crabs & I want to do what's best for them! I've been looking through others DIY crab tanks & I want to make something similar!

My ideal plan is to have *at least* 12 inches of sub, maybe 15-20. And I want the tank to be 5 - 6 feet tall, maybe 4 feet long, 2 feet deep. It will have a false bottom & two 2 or 3 gallon pools. I plan to have 2 doors that open from the front to easily access the tank.

The tank will be made of plywood & have the good stuff back ground (back and sides). And I'll be pulling apart my 40 gallon tall tank for glass panels for viewing.

But I have a couple questions for people who have made their own tanks...

What is the easiest way to heat the tank? Currently I have zoomed heat pads on the backs of the glass of my all glass tanks. I was considering putting a glass panel on the back side of the tank just above the substrate and attaching a heat mat to that and insulating it. (Along with lighting at the top of the tank)

I want to make this tank as low cost as possible. I'll be using plywood I have lying around, a 40 gallon tank that I have no use for, I'm going to attempt to spend under 300$.

Then, hopefully, I'll sell off both my hermit crab tanks as hermit crab tanks & try to pay for at least half the costs.

It's going to be a big project. & I'll just keep updating this post on my progress. But, I don't plan on starting it until summer anyways, so I have lots of planning time

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So here's the thing - the tank needs to be made waterproof, or the chemicals from the plywood will leach into the air and substrate of the tank and possibly poison the crabs. The reverse will also happen - the moisture will get into the plywood and rot it very quickly. Great Stuff foam is a.) not waterproof, and b.) easily destroyed by the hermits. Also, that much space is not going to be able to be heated with a small pad, especially up North where our winters are ridiculous!

There are not very many crab-safe waterproofing options for wood. Your standard deck or basement stuff is toxic to them as it cures by releasing harmful chemicals and can do so for years. Instead, it needs to be a 2-part product, which cures by chemical reaction and then becomes inert. There are pool paints, marine epoxies, regular epoxies, and fiberglass resins that can all work, but they all cost a minor fortune. Ideally, anything that is used should either be for potable water (meaning human-grade drinking water) or have a good history of use among DIY aquarium builders or DIY frog vivarium builders. Those two groups have the most experience with building custom enclosures and not wanting to end up with dead animals in the process due to the costs involved.

The size you want is close to what I'm going to do this year, and my budget is $400 total. I talked about how we came up with our plans and the pros and cons of the different options here: viewtopic.php?f=39&t=109765