cactus treatment and idenification

hi
i just moved house and there a 3m tall cactus. Could anyone help me out for species? using google image in looks like some sort of Echinopsis?
what sort of treatment does a cactus like this need

 

its a cereus, not an echinopsis. Its care is dependant on what part of the world you live in.

 

Just forget about it, don't overwater, which shouldn't be a problem down there as your climate is fairly dry and hot in summer, I never water any of my cacti/succulents, they get a drink only when it rains

Ed