Problem
The dentist has prescribed maxillary and mandibular alginate impressions for a patient. The dental assistant follows the dentist's orders and obtains both impressions. In the laboratory the dental assistant begins to pour up the models using model plaster and mistakenly adds too much water, making the mix too runny. The dental assistant decides to add more powder to the mix to make it thicker. Why is this wrong thing to do and what can the dental assistant do to the mix to correct it?