Filter underdrains and air scour systems become clogged with the same deposits that accumulate on filter media, reducing production and efficacy of backwashes, increasing both down-flow and backwash head pressures in addition to escalating water and energy usage. Increased backwash head pressures can lead to catastrophic failure of the filter. Prior to the Floran product line, the only practical way to deal with clogged underdrains was to remove the filter media and replace the underdrains or clean them by hand. The process for cleaning underdrains is an extension of the media cleaning process. Blue Earth Products’ products can be dosed to assure that the reaction penetrates to and cleans the underdrains in-situ. The process removes all types of organic and inorganic deposits including biofilms, iron, manganese and calcium scale. The process is safe for application by plant personnel.