Cl. 1308b 3/02; E0411 3/20 U.S. Cl. 134-3 7 Claims ABSTRACT OF THE DISCLOSURE A method of cleaning swimming pool surfaces of dirt, algae, mineral stains and other material, without draining the pool, wherein a cleaning head is moved along the pool to define, with the pool surface, a substantially enclosed space and wherein liquid, in the form of a muriatic acid and water mixture, is delivered in t