What Professional Aquariums Choose for Their Tanks

Professional aquariums use acrylic and glass tanks built to custom specifications, with acrylic dominating because it's lighter, more durable, and easier to shape into large curved displays. The tanks themselves are only part of the system—what matters more is the filtration, circulation, and life support equipment built around them. A public aquarium's tank might hold 100,000 gallons or more, but the real engineering is in the pumps, filters, chillers, and monitoring systems that keep the water chemistry stable enough for thousands of animals to survive in an enclosed space.

The choice between acrylic and glass depends on tank size and purpose. Glass is cheaper for small to medium tanks and resists scratching better over decades, but it's heavy and breaks if struck hard. Acrylic can be molded into the curved walls and domes that make large displays visually striking, and a 6-inch-thick acrylic panel weighs far less than the equivalent glass. Both materials require different maintenance routines and have different lifespans—something aquariums factor in when planning renovations.

Key Takeaways

  • Professional aquariums use acrylic for large displays because it's lighter and can be shaped into curves, and glass for smaller tanks where durability and clarity matter most.
  • The tank material is less important than the filtration system—most public aquariums use closed-loop systems with mechanical filters, biological filters, and chemical filters working together.
  • Large aquariums maintain water temperature with industrial chillers and monitor salinity, pH, and oxygen levels continuously with automated sensors.
  • Acrylic tanks need regular polishing to stay clear, while glass tanks scratch less but are much heavier and harder to repair if damaged.

Acrylic Tanks and Why Large Aquariums Prefer Them

Acrylic dominates the large public aquarium world because it can be cast or molded into shapes that glass cannot match. A curved acrylic wall creates the illusion of depth and lets visitors see into the tank from multiple angles without distortion. The Georgia Aquarium's main tank, which holds 6.3 million gallons, uses acrylic panels up to 2 feet thick. Acrylic is also transparent enough to rival glass—when new, the difference is invisible to the eye.

The downside is maintenance. Acrylic scratches easily, even from soft cloths, and requires special polishing compounds and techniques to restore clarity. A single careless cleaning can leave permanent marks. Over 10 to 15 years, an acrylic tank accumulates enough fine scratches that visibility degrades noticeably. Aquariums budget for periodic re-polishing or panel replacement as part of their operating costs. Acrylic also expands and contracts with temperature changes more than glass does, which means the seals around panels need regular inspection.

Glass Tanks for Smaller Displays and Holding Areas

Glass remains the standard for tanks under 10,000 gallons and for behind-the-scenes holding and quarantine areas. Glass is harder to scratch, so it stays clear longer with routine cleaning. It's also cheaper to manufacture in standard rectangular sizes, and replacement panels are easier to source. Many aquariums use glass for their working tanks—the ones where staff feed animals, treat sick fish, or house new arrivals before they go on public display.

Glass has real limits at scale. A tank 20 feet wide and 15 feet tall needs glass panels so thick they become impractical to handle and install. The weight also matters: a glass panel 10 feet by 8 feet by 1 foot thick weighs around 5,000 pounds. Acrylic of the same dimensions weighs about 1,500 pounds. For a building's structural engineers, that difference adds up across dozens of tanks.

Filtration Systems That Keep Water Habitable

The tank material is almost secondary to the filtration system. A professional aquarium's water passes through three types of filters: mechanical (which traps particles), biological (which uses bacteria to break down ammonia and nitrite), and chemical (which removes dissolved compounds and adjusts pH). These filters run continuously, 24 hours a day, and are sized to process the entire tank volume multiple times per hour.

Most large aquariums use closed-loop systems where water is pumped from the tank through filters and back. The flow rate is enormous—a 100,000-gallon tank might have water circulating at 2,000 to 3,000 gallons per minute. Backup pumps are standard because a single pump failure can kill the animals in hours. Aquariums also use protein skimmers (which remove organic waste before it decays) and UV sterilizers (which kill parasites and algae spores) as additional layers of protection.

Temperature Control and Water Chemistry Monitoring

Maintaining stable temperature is critical because most fish and marine animals have narrow temperature ranges where they survive. A public aquarium uses industrial chiller units that work like giant air conditioners, removing heat from the water. Cold-water tanks (for penguins or salmon) need chillers running constantly. Tropical tanks need heaters instead, but the principle is the same—automated systems keep temperature within 1 or 2 degrees of the target.

Water chemistry is monitored by sensors that measure pH, salinity (for saltwater tanks), dissolved oxygen, and ammonia levels. These sensors feed data to a central control system that alerts staff if anything drifts out of range. Some aquariums use automated dosing systems that add chemicals to correct pH or salinity without human intervention. This level of automation is necessary because manual testing and adjustment would require staff to be present constantly, and even small delays in response can stress or kill sensitive animals.

Saltwater vs. Freshwater Systems

Saltwater tanks are more complex than freshwater ones because maintaining stable salinity requires constant monitoring and adjustment. Salt water is denser than freshwater, so the same tank holds more weight—structural engineers have to account for this when designing the building. Saltwater also corrodes metal faster, so aquariums use stainless steel or plastic fittings instead of brass or iron.

Freshwater tanks are simpler to maintain but still require careful filtration. Many aquariums use freshwater tanks for river and lake exhibits because they're easier to manage and the animals are often hardier. The choice between saltwater and freshwater depends on what animals the aquarium wants to display and what the local water supply can support—some regions have water chemistry that's naturally closer to saltwater, which saves on adjustment chemicals.

Behind-the-Scenes Holding and Quarantine Tanks

For every gallon of water on public display, an aquarium has several more gallons in back-of-house areas. New animals are quarantined in separate tanks for weeks or months to may support they're disease-free before joining the main display. Sick or injured animals are moved to treatment tanks where staff can monitor them closely and administer medicine. These tanks are usually smaller, simpler glass systems with basic filtration—function matters more than appearance.

Quarantine tanks are often kept at different temperatures or salinity levels than the main displays, so they need independent climate control. An aquarium might have 50 or 100 small quarantine tanks running at any given time, each one a separate system. This redundancy is expensive but necessary—a disease outbreak in the main tank could wipe out years of breeding work or kill irreplaceable animals.

Frequently Asked Questions

Why don't aquariums just use one giant tank instead of many smaller ones?

A single massive tank would be structurally difficult and risky. If the filtration fails or a disease spreads, everything dies at once. Multiple tanks let aquariums isolate problems, quarantine new animals, and maintain different water conditions for different species. It's also easier to repair or clean a smaller tank without disrupting the whole system.

Can acrylic tanks last as long as glass tanks?

Acrylic typically lasts 10 to 15 years before scratching becomes severe enough to warrant replacement or major re-polishing. Glass can last 20 to 30 years or longer with routine cleaning. Both eventually need maintenance, but glass stays clearer longer if it's not scratched.

How often do aquariums change the water in their tanks?

Most professional aquariums don't do full water changes. Instead, they use continuous filtration and partial water changes—removing 10 to 25 percent of the water weekly or monthly—to maintain chemistry. A complete drain-and-refill would stress the animals and disrupt the bacterial colonies that filter the water.

What happens if the power goes out at an aquarium?

Aquariums have backup generators that kick in automatically. Without circulation and filtration, oxygen levels drop and ammonia builds up—animals can die in hours. Generators may support pumps and chillers keep running until power is restored.

Do aquariums use tap water or special water?

Most use treated tap water that's been filtered and adjusted for pH and salinity. Some aquariums use reverse-osmosis water (water that's been purified by forcing it through a membrane) to remove chlorine and other chemicals. Saltwater tanks require salt to be added to freshwater, or they use pre-mixed saltwater delivered by suppliers.