LOL I am sorry but I just had the same problem I bought a wale pool too , without the slide but witha built in sprinkler. it showed 3 kids around 6 years old looking sitting happly up to there waist in water , I blow it up and its like the one you ahve TINY TINY TINY its litterly about 2 inches deep at the max fill line.
Good idea wifezilla , Ill even take it in blown up maybe that way they cant say oh well the box says right ... though I bet my chicks would like it filled with sand huh