Chelants such as EDTA and NTA are molecules which have sites to form complexes.They are generally weakly acidic in nature. Chleants are particularly useful because the complexes that they form are water soluble. This allows suspended solids contained in the feedwater to be solubilized or contained in the solution. This reduces the amount of cycling in the boiler and increaes the period of operation between blowdown. Chelating agents are used to treat iron oxide and additional hardness ions that are found in the boiler feedwater stream. These ions are present due to the water added to the boiler feedwater stream to maintain the level of the boiler drum. This water is called the makeup water. The chelatn is added the feedwater side of the pump discharge line. This is done in order to form the complex prior to the entrance of the boiler drum. Control must be maintained over the chelant feed stream in order to prevent the chelant from complexing with the magnetite film formed on the boiler drum. This film acts as protective layer to the boiler unit surface. Unfortunately, the chelant may not complex all of the suspended solids in the boiler drum. A dispersing agent needs to be added to prevent any additional particles that remain uncomplexed from growing larger. Dispersants are anionic polymers which impede the crystal formation of the suspended solids. Dispersants cact to surface to surface and particle to particle attractions which are the primary mechanism for the agglomeration of suspended solids in the boiler drum.