Abstract: An improved device for soaking up water that is collected in the bottom of an oil tank, and removing the water therefrom; the device comprising a porous envelope lowered by a tethering line to the tank bottom, the envelope containing sinking weights and Sterculia Lychnophora Hance powder which is unaffected by oils but which readily absorbs water in great volume by being expandable to over fifteen times its original size when fully saturated, thus effectively removing the water when the device is lifted from the tank.