Includes an Annual buyer's guide.... Sand O Cleaning of sand in swimming pool ^* filters overnight is accomplished with a new chemical agent, Bromox, placed on the ... The company also offers a simple and inexpensive device for installation on the filter system for periodic cleanings without opening manhole. ... Model 62405 operates on standard 1 1 5v A.C., Model 62406 on 230v. ... eliminating the need for underground pits, gravel boxes, drainage lines, sump pumps, special insulation and electric neating coils hasanbsp;...