We’re happy to report that construction work on our new exhibit, set to open this year, is going swimmingly.
Preparing the shell
All the acrylic windows are in place and have been sealed by a team of experts from Clax Italia – they came all the way from Italy and we even named our youngest rockhopper penguin after them.
Says Two Oceans Aquarium Technical Manager Mike de Maine: “The windows are sealed into place with silicon. The silicon is pumped into the gap between the window and the walls. It bonds onto the wall and the window, creating a seal.”
The new exhibit – including its concrete walls and acrylic windows – will have to hold 1.6 million litres of sea water when it’s fully operational, so sealing and waterproofing is the first, most-important part of the job before design and rockwork can be implemented, and animals can be introduced.
The big water test
“The big water test is done to triple-check that the waterproofing and silicon seals are all good,” says Mike. “The tank is filled with the full 1.5 million litres. We look for leaking window seals and any bubbling of the waterproofing. The test runs for eight days. Sometimes it is only when we empty the tank that the bubbling of the waterproofing may show up.”
Into warmer waters
Once the “big water test” is complete, implementation of design and rockwork can start.
For this, Assistant Curator Claire Taylor and her team have some exciting things lined up. “We are looking at having a display with warmer water: a temperate reef with water between 21 and 24 degrees Celsius. That’s much warmer than our current Ocean Basket Kelp Forest Exhibit, which is at around 17 degrees Celsius.”
Of course, warm-water habitats look very different to colder-water habitats, so the exhibit’s design and rockwork, as well as the species that we display, will reflect that.
Designing an optimal environment for fish in a contained space is a careful balancing act.
“Out at sea, something on a massive scale looks normal, but if you try and put that into a smaller space it looks completely odd. What looks good at sea has to be adapted quite dramatically to look good in a contained environment like ours,” says Claire.
“Our first priority is to take the needs of the various animals into account. It’s a case of having enough open, sandy floor-surface space for certain species, while providing rockwork with enough nooks and crevices for reef inhabitants to hang out in, and we’ll also have fast-swimming fish, so you don’t want to limit their swimming space.”
While we do have a “wish list” of fish that we would like to display, we don’t know for certain what we’ll host until much closer to opening time. Because we don’t “shop” for fish, but rather collect from the oceans around us, our collections are hugely seasonal. Also, the species we open with are probably going to be completely different two years down the line – this is a highly changeable, and exciting, environment.
Keeping it clean
Once we’ve designed the most comfortable space possible for the animals in our displays, we will work to ensure that the water quality is ideal for them. Through a process of “bio-filtering”, which uses bio-material, like bugs and bacteria, to clean water, the water will be kept at optimum quality.
“Sub-gravel and filters will clean our water,” says Claire. “So that’s the next phase, after getting all the pipe work in, placing the blue chip, shade cloth and sand.
“The blue chip covers pipes on the ground, creating a massive surface area for bacteria to start cleaning the water. The shade cloth keeps the sand from blocking any pipe work, and then the sand goes on top of that, which is for aesthetic purposes.
“Then it’s a case of seeding the tank with bacteria to start the natural nitrogen cycle, which is what ensures that the water quality is good and livable for the animals.
“Once the filters and biofilters are running correctly, our oxygen levels are great (at 80%+ oxygen), and the temperature and pH levels are stable, we’ll start moving animals across.”
More changes coming!
When we open our new exhibit, we will be temporarily closing down our existing I&J Predator and Ocean Basket Kelp Forest exhibits for maintenance. The existing exhibits are going down for maintenance of the lining and concrete, which hasn’t been done in 20 years. It's also an opportunity to upgrade certain things, and to rethink the design of the exhibits and the animals which we want to display.
Many of the animals currently in the exhibits, like the ragged-tooth sharks, will be released. Others will be kept on- and off-site until the exhibits are ready to house them again.
Watch this space as we reveal more exciting developments in the weeks to come. Hint: it rhymes with “belly”…