A gravel filter is a great way to keep your tank clean. It doesn’t cost much to make, and it can last a very long time.
The first step in making a gravel filter is to choose the proper size of gravel. Gravel should be well rounded and sorted, rather than local angular rock. It should also be sized to be permeable enough to allow water through.
Another step is to pour a layer of gravel or other porous media into the bottom of the filter. This will help with water circulation and will also provide a surface for denitrification, which is important for reducing nitrate levels.
This step is optional, but it is always a good idea to add a thicker layer of gravel or other porous media than the one you originally used. This will help prevent the sand from clogging, and it will also serve as a place for beneficial bacteria to colonize.
A small layer of mesh (not a gravel tidy) is also helpful for keeping the layer in place. If you don’t use a mesh, weeds will grow up through the gravel and it will be more difficult to keep your tank clean.
Choosing the right gravel for your tank
The type of gravel you will use in your filter is very important. Some types of gravel are choking hazards for some fish, and they can become lodged in their throats, which will block their breathing and cause them to have other problems.
Other types of gravel can be too small for the tank, and they may clog the pipes and prevent water from passing through. Some varieties of plants, particularly those that have deep roots, can become trapped in the gravel and cause the filter to stop working.
If you’re not sure how much gravel to use, it’s best to start with a small portion and slowly work up to the full amount. This will allow you to see what size gravel works best in your tank and which ones are prone to clogging and need to be replaced.
Once the gravel is in place, it’s time to plant the bog area with plants. You should use a mix of different plants, ideally 10 – 15% of the total area in your pond.
When the bog is filled with plants, gently shovel in the rest of the gravel until it is at the correct level. This ensures that the bog will be above the water level and is therefore a safe place for fish to swim.
The bog should be at least 8 inches deep in order for the filter to work properly. The bog should also be located where it can be easily accessed for maintenance and cleaning.
You should also consider piping the bog to a storage tank so that you can get access to clean water when you need it. You can also use the bog as an aerator for the pond, which is a great idea if you have hard water fish or algae that need to be removed from the pond.