Originally I had planned on a 24x18x12 tank for my hermit crabs, but I’m wondering if 18x18x24 would be okay as well? I also found 29 gallon tanks for cheap, so I would likely go with that if not. A 29 gallon gives 360 sq inches of floor space while the 18x18x24 gives 324 sq inches but has more climbing room and the ability for me to add a second level. This is for 3 hermit crabs btw. Thanks!