Time to answer questions!
Temperature: 22-26°C / 71-79°F depending on where you measure (the closer to the heatlamp the warmer, in it's proximity on the background there are actually about 33-35°C/ 91-95°F, though only on a small spot)
Humidity: 70-99% (again depending on where you measure)
Due to the different climates within the tank the crabs can freely choose where they want to be, whether they want to be a bit warmer with less humidity or a bit colder with higher humidity.
I'm using a Lucky Reptile Thermo Control Pro 2 to control the 150 watt ceramic heatlamp, that and the 2 heated aquariums keep the crabitat nicely warm. For the humidity I am just running a "Dragon Magic Fog" fogger (I run it 5 times a day for 10 minutes) and spray the tank down every couple days.
Since the aquariums are heated too they have some evaporation that also helps at keeping the humidity up. I also have lots of airflow, so mold is no problem whatsoever.
For lights I just use floodlights and some cheap plant growing lights (two from a local store and one from Ikea lol)
Here is a picture of the lightning situation:
I don't use any equipment what so ever for airflow. I just rely on the good old "warm air rises up", I have 5 holes (covered with fine metal mesh) on the top and three holes in the side. They are about 10cm/4 inches in diameter. The air in the crabitat is not stale at all, just very humid/warm. So it seems to be working fine.
Equipment for the pools: Each pool holds 54 liters/ 14.2 gallons of water, I use a 50 watt Tetra heater for each and some small 5 watt filter, as I don't have any fish in there the filter doesn't need to be huge. I just want a bit of water movement and a bit of filtering. I added the 35 watt floodlight above the freshwater tank as it was too dark for the plants to survive (you know it's bad when a javafern doesn't thrive), since then it is nicely lit up.
Here is a link on how I built the crabitat, I hope that'll solve the question on how I implemented the aquariums.
https://imgur.com/a/xGkK0zs
For the background (I can not recommend it): I have the process in the link above, but in case I didn't write it out/document it properly: I basically covered the whole back/sides of the tank in expansion foam for wells, it is water resistant and won't go bad with the humidity. While it was still fresh I added the grapevine to it and added some more foam to the ends to anchor it in place.
As you may see in the playlist I tried to cover it in Aquarium silicone and tried to adhere coco-fiber substrate to it to give it a nice look. Well, that didn't work out, I'd guess because I didn't peel off the shiny layer, which led to the silicone not sticking. I could pull it straight off again.
So I had to rip off the shiny expansion foam layer, that process took about 2 weeks or so as I didn't want to use tools to keep a somewhat natural look (my fingers hurt so bad lol).
When I was finally done with that I decided to just cover it all in tile adhesive, it gives a rock like structure which is grippy enough for the crabs to climb on while also being sturdy and, when it is dry, doesn't release any chemicals and becomes inert (like the expansion foam). It was also really cheap as a 20kg bag of that stuff costs like 10€, and you can get a lot out of 20kg.
I put on 3 layers of that stuff so it's thick and not brittle.
In the end it worked out somewhat fine, but I wouldn't do it like that again. Next time I'll just put giant cocofiber mats all around and add structures on to that.
Owner of 24 crabs in 200 gallons. 7 C.Perlatus, 2 C.Lila, 3 C. Rugosus, 12 unidentified C.Species
Started only 3 years ago and already hooked.