CLEARWATER — David Yates' favorite type of visitor to the Clearwater Marine Aquarium is one who hasn't been there for a while.
Those visitors are often amazed at the recent transformation of the aquarium from dank, dark and musty to sunny, bustling and airy, he said.
"We constantly get 'Wow!' " Yates said in his office at the aquarium, where three of the facility's four dolphins — Winter, Hope and Panama — frolicked in a recently opened stranding pool, complete with a hydraulic lift to easily raise them for medical examinations and other purposes.
Since Yates took over as the CMA's chief executive early in 2006, the nonprofit rescue, rehab and release facility has put $6.4 million into infrastructure improvements. This year, aside from the new stranding pool, a sophisticated pump and filter system debuted, complementing other recent improvements in water quality.
The aquarium's facility in Island Estates is a 55-year-old former city sewage plant and, through the years, people sometimes commented that it still looked like one.
"We were known as a mom-and-pop facility. People kind of accepted the dirty walls," Yates said.
But managing a slow descent wasn't what Yates had in mind when he took the helm. He knew a major overhaul was needed.
"We did it because we recognized we had to," he said.
On Nov. 5, Clearwater voters will decide whether to allow the city to negotiate a 60-year lease with the CMA so the aquarium can build a new $160.5 million facility on the downtown property where City Hall now stands.
If the referendum passes, the money invested in the current aquarium won't be wasted, because it will convert to mainly a marine hospital and rehab facility. The new aquarium would become the primary tourist attraction, home to Winter, the star of the movie Dolphin Tale, and many of the other animals now living at the aquarium.
And if the referendum fails, the current aquarium still needed to be updated for its resident animals, Yates said.
Some of the upgrades are easy for visitors to spot. A gleaming new operating room can be glimpsed from the gift shop. The operating room, in part outfitted with equipment donated by Morton Plant Hospital, is nearly four times as big as its cramped predecessor. That allows for more people and sophisticated equipment, Yates said.
"It's high tech, it's bigger. Sometimes you have seven or eight people working in there," he said.
A dozen new turtle tanks and a quarantine area are also visible from the new stranding pool.
However, many of the recent improvements aren't visible to most visitors.
A huge walk-in freezer keeps the aquarium's restaurant-quality fish, which is fed to the animals, in a hard freeze, eliminating the threat of bacteria.
Offices and administrative space have been added.
But one of the pricier investments was the big upgrade in the quality of water in the animals' tanks.
Ducking into a low passageway from an outside wall, Michael Hurst, the aquarium's vice president of operations and zoological care, points below a thrumming row of water pumps and filters to illustrate how far the facility has come.
One pump and filter rests on a battered wooden table. The others rest securely on concrete blocks.
"From the old system, it's night and day," Hurst said.
Outside, there's another bank of gleaming pumps and filters, some of them servicing the new stranding pool where the dolphins are staying while their main pool inside is being painted.
Having the new pool means the dolphins don't have to be transported to aquariums in Tampa or Sarasota when their pool needs to be repaired. That saves the animals a lot of stress, Yates said.
Dr. Michael Walsh, a professor in the University of Florida's veterinary program and the CMA's contracted veterinarian, pointed out that temporary moves to other aquariums were especially difficult for the elderly dolphin Panama, who is deaf and therefore can't use sonar to navigate around a tank. The resulting disorientation in a different tank is stressful.
Being able to stay with Winter and Hope eases stress for all of them, especially Panama, he said.
"They're part of a little group and it helps her adaptability," Walsh said.
Many of the improvements began before Dolphin Tale's successful 2011 release brought fame to the Clearwater aquarium, but the movie money has helped move things along, Yates said.
"Before the movie, we were like this," said Yates, extending his arm on a slightly upward angle. "After the movie, we went like this," he said, his arm pointing nearly straight up.
And there's more good news. Dolphin Tale 2 is in the works, and the aquarium will again be the primary filming location. Principal photography is expected to begin in mid October.
Charlie Frago can be reached at email@example.com or (727) 445-4159. Follow @CharlieFrago on Twitter.