Marty Grabarkewitz is senior applications/sales engineer for SJE-Rhombus, 22650 County Highway 6, Detroit Lakes, MN 56501, 218-847-1317, www.sjerhombus.com.This article is based on Marty's presentations at past events for the Submersible Wastewater Pump Association. At SWPA's upcoming seminar, SJE-Rhombus engineer Adam Shonkwiler will be presenting. For more information about the seminar, please go to www.swpa.org.