Living Planet Aquarium half price membership

Today Living Social has an adult and child annual membership for $18.  That's half the normal price.  You have to redeem the voucher by December, then your pass will be good for a year.  We LOVE the Living Planet Aquarium.  Here's a link to the deal:  https://livingsocial.com/deals/78782?ref=conf-jp&rpi=20991769