Octopus are extremely sensitive to copper (at levels lower than most test kits can detect) so it is essential that the tank has never been used for any copper based meds or had copper wire, ornaments, light fittings, pipes etc in it!
You will also need to think about food! Cephalopods are hungry critters! Marine food is best, so crabs, shrimps etc are perfect, FW only as a treat. Some can be trained to take dead food off a stick but many will only go for live food. Same goes with snails and bivalves some will eat them others won't, some will eat them at certain life stages and the refuse them later!
Waste removal, you will need a VERY stable system, cephs put out several times as much waste as a similar size fish and they are sensitive to water quality. Over filtrate! and be religious in water changes!
Finally as daddysquoc said, you generally can't have more than one octopus per tank, they WILL fight to the death in most cases (there are and have been exceptions but these are rare). For a Bimac size you will need a 55G tank at the minimum, vulgaris MUCH MUCH larger!
Of course in a research system you may have access to more than one tank?????????
Oh and Duct tape is your friend!!!!! Just putting a lid on isn't enough.......it will need to be secured and any gaps bigger then the beak need to be sealed or you will be spending your days on an octopus hunt! Bricks on the lid are good too, if you don't mind the look!