The only way to effectively control iron bacteria is by chlorinating the well on an annual basis. Well chlorination should be performed in the spring and the fall. It is especially important to also get the chlorine out into the aquifer material surrounding the well screen, Figure 2. Annual chlorination of a well is needed to control iron bacteria. I recommend using common household bleach for a couple of reasons.
Chlorine is a noxious and dangerous gas.
Household bleach is the safest form of chlorine to handle because of its low level of chlorine. Second, it is easy to obtain as almost all grocery and convenience stores have it in stock. Irrigators with oil-lubricated, deep well turbine pumps should be especially careful if they use HTH to chlorinate their wells. It is common for these wells to have a layer of oil on top of the water. Mixing chlorine and oil can have explosive repercussions, so if a granulated or pellet form of chlorine is used for chlorination, mix it with a suitable amount of water before pouring into the well.