It took until 1 a.m., but determined seniors from Edina held their seats at a marathon City Council meeting last week to make sure the Edinborough Park swimming pool stays open.

And it will, the council decided, even as much of the indoor park at 7700 York Av. S. changes.

Towering and teetering trees will be removed, the lower grotto will be filled in and lighting will be replaced with more-efficient bulbs. Fees will increase, and the Edina Swim Club will become a major user of the pool, making it their main training facility for swimmers age 12 and younger.

A consultant had recommended closing the pool after the city decided to reexamine operations at the pioneering indoor park, which after 25 years is showing its age. Council members were concerned that the park was losing too much money, and consultants had suggested changes that included filling in the pool to create a soft play area for young children.

But seniors who use the pool for aerobics and lap swimming rebelled, saying the extra-warm pool was ideal for keeping joints loose and lives young. In the end, the council went along, partly because they think more people will use the pool if the city markets it and partly because filling it in would be very expensive.

Mayor Jim Hovland praised the compromise and said that while the city has to be cost-conscious, it can't expect all services to make money. He called the pool a quality-of-life amenity that can "sustain some losses. But we don't want them to be huge losses."

Edina resident Rita Acker, who takes aerobics classes at Edinborough and helped start a letter-writing campaign to save the pool, was elated by the council decision.

"I'm thrilled to death," she said. "I think we've saved our pool. I think the mayor was right in saying that everything we do doesn't have to make money."

This year, running Edinborough is expected to cost about $1.6 million while the park brings in less than $1.2 million in revenue. Parks and Recreation staff figured out how to shrink that gap by tweaking lighting and cutting one employee, which together should save about $120,000 a year. Capturing the swim club as a major tenant starting in September will bring in an additional $48,000 a year.

The park also is supported by more than $217,000 a year in association fees from nearby housing and hotel developments that in turn allow residents and guests to use the park. State law prohibits those agreements from automatically renewing, so the payments will end between 2017 and 2021 unless renewed.

Association representatives have told the city that they would be interested in renewing those agreements, which cost residents about $15 a month. But some council members said they were uncomfortable doing major work on the park until they know if those groups will renew their agreements with the city.

In a compromise, the council did not commit to planned pool improvements that include replacing the pool shell and deck and wall tile and creating new locker rooms. City staff said those projects could be bumped back a year or two.

In the meantime, the city will begin marketing the pool, which many users say they did not know existed until a doctor or friend told them about it.

Mary Jane Smetanka • 612-673-7380 Twitter: @smetan