Water Carnival500 Chiropractors Open Convention AlsoDetroit Lakes, June 37—The sixth annual water carnival opens heretonight, expected to attract 30,000 visitors over the weekend.Today’s attendance was swelled by 500 practitioners from five states attending the annual convention of the Minnesota Chiropractic association, who win select a posture queen from contestants in the I northwest beauty parade at 7:30 p. m. Saturday.Scheduled speakers include Dr.Vinton P. Logan, St. Louis, and Dr. S. J. Burich, Indianapolis.Water carnival highlights, in addition to the big Saturday evening parade, include the $600 outboard motor races at 3:00 p. m. Sunday and the Miss Northwest contest at 7:30 p. m. Sunday. At this time la queen will be selected to represent Detroit Lakes at the Minneapolis AquatezmiaL