A brine sealant solution and both a one-step and two-step process for producing an earthen hardpan in a pond or slush pit is described. The process disperses clay in an aqueous solution using monovalent and divalent cations and bentonite clay. The dispersed clay is then used to fill the seepage capillaries. A second aqueous solution of monovalent and divalent cations and a wetting agent is applied and aggregates the clay and creates a hardpan.