In the first season, Alex in her puddle form when she "morphs" was shown to be a clear liquid that moves stiffly and can also talk to people. In the latter three seasons, when Alex "morphs", her puddle form is an opaque, sluggish gray, and her character is mute in this form.
Outdoor shots of the fictional Paradise Valley Chemical Plant feature a marquee with gold letters. These letters always misspelled the word valley as "vally" on the marquee.
The door to the math classroom on Alex's first day of junior high school features a plaque that reads, "donated by Hidden View Valey Chemical". Not only is "Valey" a misspelling of "Valley", but the fictional chemical plant in the series that donated the school's facilities was called "Paradise Valley Chemical", not "Hidden View Valey Chemical".