That red warning sign should be down now, because the King County Wastewater Treatment District says the water’s safe again in the Cove Park vicinity north of the Fauntleroy ferry dock. As we reported on Monday, an estimated 3,500 gallons of stormwater and sewage went into Puget Sound because of an “electrical issue” at the Barton Pump Station. Signs were posted by the beach to tell people to stay out of the water Now, with water testing showing no problems, the county has lifted the warnings. But the question remains, what went wrong? The pump station was upgraded a decade ago. KCWTD spokesperson Akiko Oda told WSB today that they “know there was a power sag” but are “still investigating how that affected the pump station.” The last notable overflow at the station, 101,000 gallons almost two years ago, was explained as an event where the station didn’t have a “complete” power outage, so the backup system wasn’t triggered