I see, that's good to know.
But yes, horse shoe crabs are notorious for being hard to keep in captivity because people tend to get cold water crabs and drop them into warm water and expect them to live.
Oregon, unfortunately. No option to dive for live rock or anything, as all the rock here is dense and not porous enougj, plus the water is too cold for the microfauna to survive going into warm water.
That and the added risk of running into an orca or a great white makes it a little riskier to dive here. The whites that come by, though usually not seen, tend to be 5meters+
Would there be any other way for me to obtain liverock locally?
That's good to know. Means I can actually keep them without worrying.
I intend it to be 4' tall, 4' wide, and 8' long, though I might change that to 3.5' tall and 12' long.
I would probably keep one or at max two horseshoe crabs in the tank. If, of course, I decided to keep some of them. They're particularly messy x.x