Never subscribed to keeping them in water even when the sea was literally at the bottom of the garden! I've always found that putting, them undamaged, in tens wrapped up in plenty of newspaper, and NEVER in the fridge (it kills them!!) I keep them alive in an insulated bait box with one freezer block changed every two-three days (on top of the thick layers of paper), keeps them fit for over a week. Check them every day for dead 'uns and put these in salt. I tried freezing them but found that although they still smelt of lug that there was usually more elastic than worm on the hook. I'd recommend the salting if you've got masses but once salted they must be wrapped up tight to exclude air (salt is deliquescent and will absorb water from the air reducing your lug to a salty but mushy mass!) Once threaded on, the wizened salted lug soon swells and resembles the real thing and catches fish - well I like salt on my food too!!
I havent got the room to keep bait in tanks, sheds not big enough. 
