DEP WATERS: Dep Corp. spares no visual stimuli to depict swimmers' hair problems in an ad for new Swimmers Solution shampoos and conditioners. The ad is running in May issues of Swimming World and Swim. The hairstyling and personal-care products company, with an annual $6 million budget, has stepped up advertising in recent months. DavisElen, Los Angeles, handles. Copywriter: John Robert Evans. Art director: Mark Browning.