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Discus Fish Blog

Water Filtration for an Ornamental Fish Aquarium

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 Aquarium filters are an essential piece of equipment for any ornamental fish tank.They work to break down and remove all the waste produced by the fish as well as any other organic or food waste. The filter will also provide area in which beneficial oxidizing bacteria will grow, these bacteria are essential in keeping the aquarium water clean and free of harmful toxins. Without a filter, harmful toxic waste will build up in the tank and pollute the water, killing the fish.

However, there are many different types and sizes of filter, so choosing the right one for your particular tank can become a challenge with an overwhelming number of options. Choosing the best filter is vital for the health of your fish so here are a few things to consider.

Mechanical or biological filter

There are two different types of filter to consider, mechanical or biological. A mechanical filter works by physically removing unwanted or uneaten food waste from the tank.

The biological kind, use oxidizing bacteria to convert the harmful waste build up into clean water. This creates a self-containing eco-system for your fish to thrive in.

It’s important to know both types take time to start working so you need to get your filters installed before you add fish to your tank.

External hang on the back filters

The most commonly used filters are external hang on the back of the aquarium power filters, they have a small impeller, driven by an electric motor which draws water from the aquarium, then filters this water though some filter media located in a separate compartment in the filter. Beneficial oxidizing bacteria will cultivate and live in this filter media to further clean the water by breaking down harmful toxins from fish waste and food.

You will need to clean or replace this filter media on a regular basis to remove any trapped debris and to ensure the filter is operating at peak performance. Always leave some of the filter media to ensure not to destroy fully these healthy bacteria bed needed to break down fish waste and clean the water.

Under gravel filters

Another type of filter option is the, “old school” under gravel filter. This type of reliable proven filter system has been used for many years and is very effective in breaking down organic waste, and house beneficial bacteria to keep your fish tank healthy. The under-gravel filter tray lays on the bottom of the fish aquarium, this creates a false floor for the gravel to be placed on. The tray has lift tubes built into it which an electric power head can be attached, or an air stones can be place in to creates a flow of water though the lift tube which, pulling the water containing any solid waste into the gravel then discharging clean water back into the tank. The gravel acts as the filter media trapping any debris or waste products. Bacteria which is in the gravel will break down any organic waste recirculating clean water. Oxygen provided by the air stones will both create a flow of water though the lift tube and gravel, and will also help oxygenate the fish aquarium. This kind of filtering is normally what is used by local fish and pet stores. It requires less maintenance and act as a recirculating cleaning system to keep the aquarium clean and self-sustaining. When water changes are done the gravel should also be cleaned using a gravel cleaner. These gravel cleaners can be purchased at any fish store, as they also use them to clean their tanks.

External wet-dry and canister filters

If you have a large, sophisticated set up you might require an external power filter with additional equipment which sits outside the tank. These systems work by sucking or using gravity to drain water from of the tank, through the filter which cleans it and then pumps it back into the tank.

These filters don’t need as much manual cleaning as they have more surface cleaning media inside and they can be quite versatile. If you have a large tank or fish which produce a lot of waste, this is probably your best choice, although they can be the more expensive option. Typically, these expensive wet-dry drip systems are used in marine salt water set ups, where the PH value is above 8 and ammonia is very toxic, and dissolved oxygen levels are critical to support life.

What sizes do filters come in?

When you are looking for a filter, check the packaging as it will tell you what size tank the filter is rated for, make sure the filter is big enough for the size of your tank. Look for a filter that is capable of running a tank at least as large as yours, or slightly larger than the aquarium you’re setting up. In other words, oversizing the filter is not a bad idea.

Do all filters use carbon pads?

Carbon pads can be used in several different types of filter, they contain activated carbon which helps to remove chemicals and other waste products from the water. However, they have a limited life span and have to be replaced every couple weeks. If left to long without changing they can leach back into the aquarium harmful toxins and kill fish.

Does an external filter need any extras?

If you are going to get an external filter system be sure to get a self-priming system which automatically pulls the water from the tank into the filter. This feature will make it a lot easier and simpler to operate when turning on and off.

Is it easy to change a filter completely if I get it wrong?

Yes, it is possible and simple to do. Just be sure when setting up the new filter to take some active filter media from the old filter, and use this to seed and jump start the new filter, by doing this your tank will transition quickly and it will not miss a beat in cleaning your aquarium. Another way would be to run the two filters alongside each other until the new one is mature enough to run alone. A few days running them together like this will be sufficient.

There are many different types and sizes of water filters for aquarium fish tanks so choosing the best one for your tank is a case of doing some research and making sure you pick the right system for the size of your tank the amount of waste produced.

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