Freshwater Aquarium Substrate - How to Decide

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When you think of an aquarium it is very easy to notice the fish, the plants, the decorations and even the tank, and end up ignoring what is probably one of the most important parts of the whole aquarium set up which is the aquarium substrate.

The substrate is an essential part of the whole tank eco-system. The gravel, or sand that lies at the bottom of the tank forms an important part of the whole system and helps to provide a healthy environment for your plants and fish.

It serves several purposes. Obviously it looks decorative and finishes off the bottom of the tank nicely, but it also helps in a lot of other ways, providing a haven for the beneficial bacteria that will help with the water quality.

The type of tank that you have and what is in it will vary the type of substrate that you need. If you have decided on a tank that simply contains fish and no plants then you will only need about two inches of substrate. The substrate could be fine sand or gravel but do make sure that it is suitable for any bottom feeders which prefer a fine gravel.

Too much substrate can cause problems of its own. If the substrate is too deep it will not get oxygenated very well and will end up creating a home for bad bacteria that will feed on left over food and create pollution in the tank. The problem is that as the substrate becomes compacted and food starts to build up in this layer it creates hydrogen sulphide. This builds up in the substrate and gets released when the substrate is disturbed causing a sudden increase in pollutants in the tank and possible health problems for the fish.

If you are planning a planted aquarium then the choice of substrate is probably one of the most important decisions that you are likely to make. The type of substrate that you use must not only suit your fish but must also provide essential nutrients for the roots of growing plants.

With a planted aquarium the substrate will have two distinct layers. The base layer will be made up of a nutrient rich substrate such as Vermiculite which will slowly release nutrients over time. This layer needs to be a good two inches deep to allow for the plant roots.

Cover this layer with the desired substrate of gravel or sand. This is what will give your tank its final appearance and is also the substrate that the fish will come in contact with so the decision is really on sand or gravel and then fine or coarse gravel. This will give you the look that you want to achieve and keep your fish happy in their environment.

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Nick North has 1 articles online

Nick North lives in The Midlands in England with his wife and family. He has been a keen freshwater aquarium enthusiast for nearly twenty years and passes on his knowledge and experience through his articles. He has co-written the ebook "The Ultimate Guide to Freshwater Aquariums" which is available at the freshwater aquarium website.

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Freshwater Aquarium Substrate - How to Decide

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This article was published on 2010/04/03