An apparatus intended for incorporation as a module within ground improvement pokers such as those already patented (U.S. Pat. Nos. 6,554,543 and 8,419,316) in order to enhance the field performance of those hydrodynamic compactors by either improving their ground penetration capability, and/or, maintaining or recovering the permeability of their outer seepage filtration element; involving a method which can be activated remotely at the operator's discretion, while those parent devices are at depth within the earth. This apparatus and method may have application in water well installations and reviving flow in oil wells.