When scale deposits and/or biofilm develop within the screened intervals of a well, a common effect is for the apertures to become plugged. When this occurs, a well will often experience both reduced production capacity and diminished specific capacity. As nutrients in the groundwater are continually drawn to the well by pumping, the bacterial growth is promoted.
The growth of iron bacteria can be controlled by disinfection with chlorine. Chlorine can inactivate the iron bacteria and also oxidize the iron. Control of iron bacteria with chlorine is accomplished by oxidation of the ferrous iron which deprives the iron bacteria of their energy source.
Go to a library and have them obtain the book titled "Handbook of Ground Water Development" by Roscoe Moss Company. Some of the chapters are online.
The initial treatment should be chlorination. Periodic treatments may be necessary.
Aqua Feed and QC-21 are not specific treatments for iron bacteria.
What type of well, capacity, and what does the well driller recommend?