A few days ago, I was browsing aquarium supplies when I recalled the confusion I felt when just starting out my fish keeping hobby. I’m sure that a lot of you can relate to this, so I decided to write this article to make the process of owning an aquarium much simpler. At the end of this article are links to what we have found to be the best filtration systems for both beginner and professional tanks. All of our recommendations can be found through our links to Amazon.com, which is the best place to purchase aquarium supplies because many of these exact same items in pet stores are marked up significantly.
The most important part of a healthy home aquarium is the filtration system, and the best systems make use of a combination of mechanical, chemical, and biological filtration. You can use this information, as well as the cycles per hour to determine the best tank filter for your aquarium, as we will explain below.
Do I Need a Different System for Freshwater and Saltwater Tanks?
Fortunately, the only difference between the filtration requirements between freshwater and saltwater aquariums is that saltwater tanks typically require a filter with a higher water turnover rate per hour (usually at least 6). The only time that there needs to be more advanced filtration systems is when you plan on keeping corals or delicate fish (but we will get into that later).
How Many Turnovers per Hour Do I Need?
One of the most important factors in determining what filtration system to use if the turnover rate, meaning how many times per hour the entire quantity of water in the tank goes through the filtration system. While most filtration systems will tell you the size tank they are recommended for on the package, we recommend to check for yourself how many cycles per hour the filter will do for your tank. To determine the turnover rate per hour, divide the gallons per hour the filter moves (which can be found in the filter’s manual or on the box it comes in) by the number of gallons that your aquarium holds. We recommend that a typical freshwater aquarium should cycle through at least 3 times an hour, and for saltwater tanks it should be double that. One thing to keep in mind is that tanks that contain fish fry or have delicate plants may require a slower flow rate. Also, tanks with fish that have very sensitive living requirements may require even more cycles per hour. Just make sure that the flow of the water is not too strong in the tank that it blows the fish or live plants around, or that it can trap the fish against the filter intake. If the fish are struggling to stay in place or are being blown around, lower the flow rate. Keep in mind that most filter outlets can be bent into a different direction that may be more optimal to keep from disturbing the aquarium’s occupants.
Mechanical, Chemical, and Biological Filtration
Successful aquariums make use of all three types of filtration: mechanical, chemical, and biological. They do this to replicate the natural processes in nature that keep marine life alive, and below we will detail the three types so you can be more informed about how to implement them into your aquarium.
Mechanical filtration is the first step in most filtration systems, and is key to removing larger pollutants from the water that can harm the fish, and helping keep the water clean and clear. Mechanical filtration refers to the process of removing larger contaminants from water, such as fish waste. This is most commonly done by flowing the water through a substance with small holes in it (like a sponge) that traps the larger objects but lets the water flow through. It is important to have the mechanical filtration as the first step in filtration systems to keep larger objects from damaging the other filtration steps.
Chemical filtration is done by activated charcoal, which is similar to the ash that you would find in your fireplace. This charcoal, however, has much more fine pores and an extremely high surface area that removes dissolved contaminants from the water. This is a critical step because it helps keep the water free of contaminants that are not visible to the naked eye.
Biological filtration is the third type of filtration, and is probably the most important part of a healthy aquarium system. Biological filtration in an aquarium is exactly what keeps the ocean clean, just on a much smaller level. This is the process by which beneficial bacteria in the tank and filter break down fish waste and help to keep the levels of ammonia and nitrates low. Without an effective biological filtration system, no tank would be possible. While biological filtration occurs anyway in the tank by the bacteria growing in the substrate, it receives a significant boost when proper growth medium is provided in the filter to allow the colonies to flourish. This is most commonly done by providing objects with high surface areas, such as magma rock, which allows large amounts of beneficial bacteria to grow that will then consume the fish waste.
The healthiest tanks utilize a combination of all three filtration systems, and to be successful, make sure that you do too.
Most Common Types of Aquarium Filtration Systems
Power filters (or back hanging filters) are the most common for home aquariums, and for good reason. They have a good combination of all three types of filtration, and they are easy to maintain. They also provide excellent aeration for the water. We recommend them for all freshwater tanks, however something with a little more power should be used for saltwater tanks. Power filters are typically all you will need for most freshwater tanks, but if you have a very large tank or have certain species that require very specific conditions, you can combine it with another form of filtration to make it more effective.
Canister filters are the most common type of filter used for saltwater aquariums, and offer a more substantial filtration than power filters. Offer all three types of filtration inside them. While they are more effective than power filters, they are more expensive and are slightly more difficult to maintain. However, the systems we recommend below are all relatively easy to clean. One of the major benefits of these systems is that they do not hang off of the back of the aquarium, but can be installed virtually anywhere that they pipe can run to, making them very easy to hide. We recommend these for aquarists who want a more robust filtration or do not want to have the look of a hanging filter on the tank.
Sponge filters only have mechanical filtration, but they are very effective for tanks that need very slow flow rates, such as breeding tanks with fish fry. Also, they can serve as a good filtration system for small tanks (less than 1 gallon). The downside to them is that they require frequent cleaning and do not remove dissolved pollutants.
Protein skimmers utilize a column of small air bubbles that lift fish waste and decomposing food out of the aquarium water. While these can be great additions to saltwater aquariums and help to keep the water much cleaner, they are not necessary for most tanks, unless you plan on keeping corals or delicate organisms. Also, if your tank is overstocked (which you should not do in the first place) protein skimmers can help you to keep the pollutants under control, as well as if you are just having difficulty keeping the pollutant levels in check. They might be a good addition to very large tanks with fish that produce heavy waste that could potentially clog the main filtration system. While they can be installed on freshwater tanks, they work most effective in saltwater.
Fluidized Bed Filters
Fluidized bed filters are a more advanced biological filtration system; however, they need to be combined with another filtration system to be effective. These types of filters suspend thousands of small objects with really high surface areas in water (such as beads). They provide a significant surface area for beneficial bacteria to grow, and collide into each other by means of a bubbler to knock off and large particulates. These systems are very noisy, but can be very effective on larger tanks that need a biological filtration boost. Because of their noise, they are commonly installed in a separate room for tanks that require large filtration systems.
As the name implies, trickle filters trickle water down on to biological growth media that break down the fish waste and excess food in the tank. These are very effective biological filtration systems and they provide excellent aeration for the water, but they should be installed in conjunction with another filter type because they do not offer mechanical or chemical filtration. These systems should only be installed on larger aquariums because of their size, as well as their cost. They don’t require much maintenance, however, only infrequent rinsing of the growth media. Most advanced aquarists have a trickle filter installed on their tank, and they are highly recommended as a biological boost in larger tanks.
Under Gravel Filter
While under gravel filters used to be very popular, we strongly discourage their use. They work by pulling water through the gravel of the tank to a filter. While this may be good for the beneficial bacteria in the gravel, they clog very easy, and make removing the fish waste from the gravel very difficult. Also, they easily damage live plants (which themselves are useful in keeping water clean). Finally, they can suck pieces of food down into the gravel that would otherwise have sat on the top of the gravel for the fish to eat, and thus they can create even more polluted water. This build up of food and fish waste can even begin to produce toxic gas for the fish, making them not a good investment.
The Best Aquarium System for Your Purpose(s)
*Make sure that whatever system you purchase is designed for your tank size (this information is found on the product packaging). Also don’t forget to buy extra filter cartridges when you purchase so that you do not run out.
Fry/Breeding Tank- Sponge Filter
Regular Freshwater Tank (Most People)– Power/Hanging Filter
Regular Saltwater Tank (Most People)– Canister Filter
Large/Advanced Freshwater Tank– Canister Filter + Trickle
In the end, the best aquarium filter for your purpose will ultimately depend on a lot of factors, meaning this guide is not what’s best for every tank. In general though, most beginners should start with a freshwater aquarium and have a power filter to get into the hobby. A canister filter would also do nicely, and would be great for a beginner saltwater tank. As you get more and more advanced, adding protein skimmers, trickle filters, and fluidized beds can help you to keep your fish and plants happy and healthy. Feel free to contact us if you are having trouble deciding on what type of filtration system to choose, and make sure than you keep checking on our website for upcoming articles to help you in your aquatic journey.
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