There are hidden depths to Dunedin's St Clair Salt Water Pool.
A sweltering summer has resulted in a record stream of swimmers getting reacquainted with Dunedin's oldest pool.
An average 400 people a day have visited the pool so far this month, following a busy 300 daily visits last month.
The 10,639 visits in December was a 17.7% increase on December 2010.
The warm weather had led to the best attendances in five years, pool manager Gaye Brooks said yesterday.
"It's been fabulous. It's really been terrific. We've had the busiest December-January I can remember.
It's a weather-related pool, so a good summer means a great season," she said.
"There's been a good mix of locals and visitors. We get the oldies in in the mornings, when it's a bit quieter, and then the families come in and then the kids dribble in whenever they wake up. But we've had families here as early as 8.30am this season, which is unheard of."
The pool was a special Dunedin asset and unique in New Zealand, Ms Brooks said.
"You're really out among it in the waves here, but you can swim in safety. You can watch the waves rolling in and it's an amazing sight.
The outdoor aspect is also a big part of it. A lot of people like that it's seawater and isn't as heavily chlorinated as indoor pools."
The St Clair Salt Water Pool is the only survivor of several salt water pools built in Dunedin during the late 1800s.
Generations of families have trekked down to the pool nestled among the rocks, between St Clair and Second beaches.
Sue Creighton and daughter Holly Smaill (16) spent years carving up the pool, before joining the St Clair Surf Lifesaving Club.
"I've been swimming at the hot salt pool pretty much my whole life," Holly said.
"I love the scenery and the temperature of the water. It's been a big part of our family."
Ms Brooks said she had "watched kids grow up here over the years".
"I remember when Holly started at primary school. Then she joined the surf club and now she's still here as a young adult. One day, she'll probably bring her kids down here."
The pool's best-known regular is 94-year-old ("I'm 95 on February 5") great-grandmother Myrtle Pearse, who is known as "Myrtle the Turtle".
Mrs Pearse, who lives at the Frances Hodgkins Retirement Village, gets up daily at 4am and is usually in the pool by 6.30am.
"I try to do a couple of lengths every day. I like to get there early, when there are only three or four other people there," she said.
"It's so warm and it's seawater, so it's lovely. When you get a bit of wind, you just get under the water. It's a really lovely sensation."
The 25m pool is heated to 28C, with a mixture of salt and chlorinated water, and facilities include six lanes, a toddlers' pool, a changing area for the disabled and a cafe.
The pool's hours have been extended this season, opening at the start of October instead of the traditional Labour Weekend.
The pool will close on March 31.
It is open from 6am to 7pm Mondays to Fridays and 7am to 7pm at weekends.
