Aeration & Filtration

Although aeration and filtration tend to be discussed together – largely because most of the common types of filters used in the aquarium rely on an air pump to work – they are separate things and serve different purposes. For those types of exotic pets which need to get their oxygen from the water, the value of aeration is obvious and for any kind of water-living pet, filtration is essential to stop them being poisoned by their own waste products.

There are many proprietary designs of filters, pumps and other equipment to choose from to help you provide the best possible environment for your pets, the choice largely depending on personal preference, tank size and the kind of animals your aquarium has to house.

Aeration

The basic idea behind aeration is very simple – pumping air through the water so that some of it dissolves, increasing the amount of oxygen available to aquatic life; how well it all works in practice depends on the amount of air supplied and the size of the bubbles.

The more air, the better the effect, so it’s important to pick a pump which is big enough for the size of tank and the smaller the bubbles, the more efficiently the air is transferred , which is why diffuser stones are used. However, it’s not just about pumping air; there are factors which affect how much oxygen the water itself can hold – and for the pet keeper, this can influence the choice of equipment.

The simple rule is that fresh water holds more oxygen than salt water, and cool water holds more than warm – which means in practical terms that you’ll have to work harder to get the same level of oxygen in a tropical marine aquarium than in a cold, freshwater one. It’s something to bear in mind when you’re planning the aeration in your tank – but don’t get too hung up on it; your dealer ought to be able to give you all the advice you need and help you find the right pump for the job.

Under-Gravel Filter

Some form of combined mechanical/biological approach is the most commonly used for filtering exotic pet tanks, the under-gravel system being one of the most popular.

The main part of this kind of filter is a perforated plastic plate which sits over the whole of the base of the tank, with a tube sticking up towards the top of the tank, down which you put an air line and an aeration stone. As the name suggests, gravel is then layered on top of the plastic plate. In use, the air moving from the bottom of the tube to the top sets up a flow within the aquarium that draws water down through the gravel, under the plate, along the channels beneath it and then up again through the tube, along with the air.

Of course, this moving current of water also pulls any waste material or other particles along with it, which become trapped in the gravel. In addition to this mechanical sieving action, colonies of beneficial bacteria build up on the gravel which do the biological part of the filtration process by helping to break down the trapped material.

Over time the plastic filter plate will tend to get clogged and the gravel will become discoloured, so it will be necessary to clean both, from time to time.

Other Options

There are various kinds of separate box units available which some people prefer for exotic pets because they are easier to clean than under-gravel filters and involve less handling of the animals themselves. They work on the same basic principle, drawing water through them to be filtered and cleaned, but instead of gravel they use some type of artificial filter material, which can be quickly removed for cleaning or to be replaced. Some types of these units are designed to sit inside the tank, while other ones are to be positioned outside.

Although many of them use aeration pumps to drive the whole process, for some of the messier aquatic pets – particularly the likes of terrapins – a power filter can often be a better bet. An electric pump sits inside the filter box – which attaches vertically to the inside of the tank, usually by strong suckers – and this pulls water in at the bottom of the unit, forces it through the filter medium inside and then back out at the top. The actual filter part itself is often contained in a removable cartridge, which again makes cleaning and replacement a very straightforward task.

Clean, well aerated water is an important factor in ensuring that your pets stay in good health; fortunately the equipment necessary is readily – and very cheaply – available, so it’s very easy to get things right in your own aquarium.