Abstract: This invention relates to a system for monitoring and controlling foam in a liquid tank utilizing a foam level sensing device positioned at a downstream location from a defoaming agent delivery arrangement. The foam level sensing device comprises a float having a plurality of foam sensors positioned at various levels above the float and provides signals to a control device regarding the level of foam in the tank. The control device provides instructions to the defoaming agent delivery arrangement so to provide a proper amount of defoaming agent to the tank. The defoaming agent delivery arrangement may be operated continuously and includes a backup delivery device for times when the delivery means runs out of defoaming agent or at times when foam is generated at an exceptional rate.