Think you'll need a chiller of some kind to keep the water cold enough, some of the lads on the sea angling forums have mentioned having cold water marine tanks before and collecting from rock pools to stock them. Best bet is contact somewhere like one of the SeaLife centres and ask for some tips from them.

Check this link: http://www.glaucus.org.uk/wetthumb.htm if you scroll down to "equipment checklist" it tells you the stuff you'll need, beer cooler to chill the water down.

 

I was thinking about the temp and thought maybe keeping a tank with water exchange kept somewhere cold I think maybe keeping an exotic species maybe a lot easier will still have a look around

 

I think you're looking at a similar problem to keepers of NZ velvet worms, it's a lot easier to keep summat warm than it is to keep it cool.

 

as above have said, they need to be kept cool, about 4c

and as much water volume as possible and mega filtration

 

I've done it with smaller crabs collected from rock pools. An adult however is going to need a pretty large set up....and tbh, i'd imagine most are pretty stressed by the time you see them at the fishmongers awaiting the pot.

They are fine if you have a decent water volume and provide plenty of food. Tidal pools are subject to large variations in temperature so they can survive at 20C or above even provided that it's not constant. I'd certainly keep it out of direct sunlight.

I also kept sea anemones for some time in the same set up and a decent community of zooplankton was still present after a good 10 weeks.

I would stress however, my attempt wasa deliberate short run, for a full time year round set up, i'd go for at least some sort of cooling. My mate Chad (Widmer - the reason I add the name is because you should buy his book, it's on amazon, haha) used to run cables into a small reservoir through a small freezer that he'd drilled holes in to cool the water for his jellies.