Blown water filter closes Hallock pool early for the season

By Anna Jauhola
A loud bang startled campers in Gilbert Olson Park Thursday evening in Hallock, prompting a call to the authorities.
“Some Canadian campers had called the sheriff’s department about a quarter after 10 and said they heard a loud bang and saw water spraying out of an open area, a vent, at the pool,” said Dan Larson, Hallock utility superintendent. “So I went down there immediately and shut everything off.”
Larson discovered the aging water filter had exploded, leaving a 7-foot crack around the top of it.
“It just opened up like a tin can,” he said.
With that much damage, Larson and city officials made the decision to close the pool for the rest of the season.
The filter is at least 30 years old, Larson said in checking with the previous utility superintendent, Tom Klegstad. Although it was maintained well over the years, the unit has worn out and has been welded several times to fix various leaks. Just last week, Larson and his crew fixed a pinhole leak in the same area, which was no different than the other leaks they’ve fixed on the filter.
The filter, which stands 5 ½ feet tall with a diameter of 78 inches, barely tops 18 psi for pressure, and it’s rated for 50 psi, Larson said. The tank is also three-quarters full of sand, which is the filtering agent.
Larson said he and his crew check on pool operations twice a day, mostly to check on the chemicals used, but also to check the pressures on equipment and the hair basket in the filter.
“It’s a high maintenance place,” he said. “Joel Peterson and I were down there Thursday afternoon about 3:30 and pressures were great. It never pressurizes, really. It loses pressure as the hair basket plugs.”
There is no explanation for why it would build up pressure and no way of telling this incident would happen, he added.
“The scary part is, to bleed air out of the system when we change the hair basket, you climb a ladder and you open a valve right there,” Larson said of where the 7-foot crack is. “So, you’re right there where it blew apart. That’s kind of scary.”
Although the city could hire someone to weld the filter to repair it for the rest of the season, Larson is not convinced it would be worth the trouble. He estimated it would take several days just to get a welder to the pool to fix the filter. Then, Larson and his crew would need to filter the entire pool to make it safe for swimming again, as the water will have turned green.
“I think we should take the money the city would spend on that and put it toward a new filter,” he said.
Larson contacted Recreational Supply out of Bismarck for a quote on a new filter. At the Hallock City Council meeting on Monday evening, he told the council a new filter will cost between $15,500 and $20,500. It would take at least six weeks to get a new filter.
The council did not vote on the issue. They will also look into whether insurance might cover the cost of a new filter and the possibility of a different filtration system.
The public is disappointed by the sudden closure, but Larson said, “It could have been worse. It could have happened in June.”