Many birds like to take their pellets and other food items and dunk them in their water bowls. Clean water can turn into a bacterial soup in short order, because bacteria multiplies exponentially by the hour in water at room temperature. For this reason, separate food and water bowls, placing them as far apart in a cage as possible, to minimize dunking. Better yet, switch your bird over to using a water bottle.
Birds are so smart that most will convert over in no time. However, check the water level in the water bottle several times per day to ensure that it is dropping, or tap the end of the sipper tube to make sure that it is not plugged up. Birds that drink from water bowls tend to have higher levels of bacteria, which may cause sub-clinical infections, than birds that drink from water bottles.
The Truth About Grit
Grit, defined as small pieces of insoluble mineral material (usually granite or quartz), is necessary for birds that consume whole, intact seeds. Birds that require grit include pigeons, doves, free-ranging waterfowl, poultry and ratites. Many seeds have a fibrous coating that will not be affected by digestive enzymes, so grit in the ventriculus helps to grind drown whole seeds.
Since psittacines and Passeriformes normally hull (crack) seeds prior to ingesting them, grit is not necessary. Parrots and passerines that consume a pelleted diet have no need for grit in the gizzard, and many parrots have gone their entire lives without ever consuming grit with no untoward effects.