What’s inside your aquarium?

The filter keeps the whole aquarium moving; it physically cycles the water around the tank.

A filter is the sewer treatment works of the aquarium; it uses foams and floss to physically remove large pieces of waste from the water, and grows good bacteria that process toxic waste chemicals into safer components. In most examples, the filter is a box that sits in or just outside the aquarium.

Inside the filter is a pump that pushes water through filter media such as foams, floss and ceramic media (the home to the good bacteria), and out the other side to re-enter the aquarium. Filters come in lots of different shapes and sizes for different aquariums but one thing’s for sure: every aquarium should have one. Find out more about your filter in this article.

Light is essential for a thriving aquarium. Well controlled, specialist aquarium lighting will provide the right type of light to help plants grow, fish thrive, and keep algae at bay.

Lighting can come from traditional bulbs, or LEDs. LEDs are the more efficient of the options, but both do a good job depending on the needs of your tank.

It’s important to control your aquarium lighting to mimic a natural cycle. Too much light will make your tank turn green with algae, and too little will leave you with dull looking fish and dying plants. Try a ten-hours-on and fourteen-hours-off routine, or use a timing device that can automate this.

If you keep fish from tropical waters, you’ll need a heater. So many popular aquarium fish come from warmer parts of the world, making an aquarium heater essential.

There are lots of different types of heaters to choose from. The most common heaters are thermostatically controlled, sealed glass tubes that contain an element. They’re often pre-set with a particular temperature, but tend to have a thermostatic controller which lets you set the temperature yourself. Fit the heater by following the manufacturer’s instructions, and be sure to use a thermometer to double check the heater is working properly.

Another type of aquarium heater available is a flat heater that’s programmed to maintain a set temperature above the ambient temperature. They constantly produce a set amount of heat, so the water temperature should be carefully monitored in warm weather. These heaters can be quite flexible and can be fitted into the aquarium in several ways. You can hang the heater on the side of the aquarium, tuck it away in the filter (depending on the aquarium design) or bury it in the gravel.

You can also add air pumps, air stones and air ornaments. They do more than look pretty; they add extra air to your aquarium, benefitting the fish and plants with extra oxygen.

Oxygen is naturally scarce in water but required by the fish, so circulating the water with an air pump helps take oxygen into the water from the surface and drives out poisonous carbon dioxide. A filter helps circulate water in an aquarium, but the best way to ensure optimal gaseous exchange is to use an air pump and air stone.

Gravel, also known as substrate, is the material on the base of your aquarium. There’s a huge variety of substrates to choose from. It comes in many shape, sizes – from almost sand to stones – and a variety of colours.

Substrates can also be artificial, with a variety of brightly coloured option available. Gravel does more than look good. It also anchors ornaments and plants, and holds nutrients to feed live plants.

No matter what you prefer, make sure you use only specialist aquatics gravel and thoroughly wash it in plain water before you add it to your aquarium.