Ashland, OH - Pentair, Inc. announced on August 10, 1999 the acquisition of ESSEF, a manufacturer of products used in moving, treating and storing water, which includes pumps, tanks and filtration systems. WellMate^tm, formerly a division of ESSEF, is now part of the Pentair Pump Group, along with member companies Aurora, Hydromatic, Fairbanks Morse and F.E. Myers.