New to the scene is Kumeu Film Studios, a converted screen production complex just 25 minutes from central Auckland. Initially built around the China-Hollywood co-produced action-adventure film MEG starring Jason Statham and Li Bingbing, the 27-hectare site (66.7 acres) now includes extensive stage, workshop and manufacture spaces, production offices, 12 hectares of forest, and two water tanks. These are the only water tanks of this size and type in New Zealand. They include:

Underwater Dive Tank (indoor):

• Volume: 1.267 million litres (334,686 US gallons/278,684 lmp gallons).
• Diameter: 18m (59.5ft).
• Maximum depth: 4.9m (16ft).
• Stair access and 6.8m2 (73ft²) platform just below water level for diver access.
• State-of-the-art Hydroxypure/Ozone water treatment system that creates crystal-clear water with maximum temperature 33°C (91°F).

Ocean Surface Tank (outdoor):

• Volume: 2.5 million litres (660,430 US gallons/549,923 lmp gallons).
• Length: 36m- 54m (118 to 177ft).
• Width: 40m (131ft).
• Depth: 0.7m to pit of 3m (2.5ft and 10ft) with the base of the pit 17m2 (55ft2) with a 9.6m2 (31.5ft2) reinforced concrete foundation pad below the liner for attaching hardware.
• Traditional chlorine treatment system with a maximum temperature 32°C (89°F).

Challenge: Creating healthy water for actors, clear conditions for filmmakers.

Before filming MEG, American movie giant Warner Bros. Studios needed assurance that the underwater dive tank was able to create a blank canvas - a default position - for filmmakers, which meant the water needed to be as clear as possible.

"When shooting underwater shots, we are usually trying to match footage to cut into a sequence that is either shot on a Location or a Surface Tank, on a previous date or to be shot in the future," says Steve Ingram, Special Effects Designer / Supervisor. "So, we need to be able to control the 'underwater atmosphere' as much as possible."

The best place to start, he explains, is with crystal clear water, which does not irritate the actors' eyes or skin.

"The lighting options and available image definition resulting from this water clarity usually deliver a better and more believable end look to the sequences. Post Production VFX work, if required, is usually a lot less complicated when you can remove a variable and often 'swirling' atmosphere out of the equation," Steve explains. "Along with the comfortable water temperature, easy access and multitude of 'rigging points' available, we are able to get the best shots possible in a very safe and efficient process."

Solution: A chlorine-free filtration system to preserve acting talent and filming equipment.

Producing the same quality of water demanded by high-end hotels all over the world (which the studio says is a major selling point they use when pitching to producers), Waterco's Hydroxypure has brought a myriad of benefits to the cast and crew.

"The actors have commented that the water feels soft on their skin and gentle on their eyes, unlike chlorinated water which causes red eyes," says Head of International Screen Production Attraction, Harry Harrison. "That is hugely beneficial for actors that need to be consistently under water for hours at a time without masks. And, unlike chlorinated pools, Hydroxypure doesn't bleach costumes or deteriorate divers' wetsuits.

"We haven't emptied the tank since it was filled," Harry adds. "A chemist tests the water every week and it has remained clean and healthy with the Hydroxypure treatment system. We haven't had any instances at all where the water has triggered any concerns from a health and safety perspective."

Conclusion: Crystal clear water for "100% Pure New Zealand."

Harry says water clarity is "absolutely critical" for underwater filming, in terms of transparency, health and safety, and the ability to control the environment - which is now all possible thanks to Waterco's Hydroxypure system.

"We are now on the radar of major international studios that are looking for facilities with water tanks," he adds. "Thanks to the size of the underwater tank and quality of water, we now have the ability to compete with film and television projects from all over the world. Hydroxypure gives us that ultra-clear, pristine water."

It's so clear, that a new Viacom television series called Shannara, which recently filmed in the underwater tank, described the footage as "cinematic."

"They're thrilled with the quality of the material they came away with," says Harry. "Also, I had two executive producers looking at the tank two days ago and they were completely blown away by the clarity of the water."

Hydroxypure, it seems, is bringing new meaning to Tourism New Zealand's marketing campaign: "100% Pure New Zealand."