Types of Planted Aquarium Filters – Sump Filters

Now that you know the different and critical types of filtration in a planted aquarium, how it relates to Mother Nature’s natural water filtration systems, and how aquatic plants aid in the water’s filtration in our aquariums, it is now time to discuss all about planted aquarium filters. 

Planted aquarium filtration is the lifeline of all the inhabitants in the tank. Aquarium filters remove physical, dissolved chemical wastes and other contaminants from the tank. Without it, you would have to change the water more frequently, and this hobby becomes a chore (you will not be able to enjoy your planted aquarium that way). It simplifies our maintenance and widens the days between water changes.

Furthermore, it affects the health and well-being not only of your faunas but also your plants. Aquarium filters are critical to support life in your tank. As I said before, our planted aquariums are a relatively small and enclosed ecosystem compared to our faunas’ natural environment. We have no running water here, and at the very least, we should replicate their natural environment by using an appropriately sized filter.

The function of an aquarium filter for our planted aquarium is not limited only to provide filtration.

  • A suitably sized aquarium filter can provide the needed water flow or turbulence to distribute the nutrients and CO2 (if you are injecting CO2, prolonging the CO2 bubbles contact with water so it can be dissolved before it reaches the surface).
  • Not just distributing nutrients and CO2, it provides the water current that some fish loves to swim against. Plants swaying with the gentle water current is a sight to behold.
  • A breeding ground for beneficial bacteria to break down harmful Nitrogenous compounds (Ammonia, Nitrites) into less harmful ones (Nitrate).
  • An aquarium filter can also provide the water surface agitation, aerating the water for our faunas and beneficial bacteria’s nitrification activities.
  • It can also prevent the accumulation of wastes, sludge, mulm in the substrate, keeping them suspended/floating so they can be taken in by the filter’s intake.

There are numerous things to consider when buying your planted aquarium filter by providing each filter’s pros and cons. Still, before we get to that and find you the right one (you can even DIY your own filter), you need to familiarize yourself with the different types of filters available in the market. Also, we are on a planted aquarium website. Obviously, we will discuss those popular filters applicable to a planted aquarium. 

So Undergravel filters, you are out! Nobody wants to rescape their planted aquariums every 2 to 3 months to clean the detritus that’s been pinned down by this filter. With the advent of aquascaping, that’s the nail in its coffin.

Types of Planted Aquarium Filters

Sump Filters

The defining features of a trickle filter are its tower and the water trickling down (vertical) the several stages of filtration, oxygenating the water well, which results in an excellent biological filtration. What if we remove that tower? That leaves us with only the sump. We defined the sump in conjunction with a trickle filter as just a holding area for the filtered water before it gets returned into your main tank. A sump can be a normal tank or water container below your main tank. But how can we make a sump to provide filtration?

Think about a trickle filter as vertical filtration stages and a sump filter as a horizontal one by utilizing chambers separated by baffles to route the water horizontally (as you can see in the diagram below). The main takeaway here is that the filter media are always wet/submerged in water as opposed to a trickle filter.

A sump filter can be positioned below your main tank, overhead, or integrated.

How does a Sump filter work?

For a sump filter under your main tank, like a trickle filter, a sump filter starts with some overflow system letting the water overspill from your main tank and then will drain into your sump filter (no drip plate here) with the help of gravity. If you don’t want to drill holes into your main tank, you can use two submersible water pumps: one from the main tank to pump water out and two, from the last chamber of the sump to pump filtered water back into your main tank. The pump that will pump filtered water back into your main tank should be more powerful as it needs to overcome gravity.

There are also sump filters that are integrated into the main tank, complete with the overflow system. You can even DIY your own design and can have limitless room for customizations (if you are handy). 

As I said above, the filter media are always wet/submerged in water instead of a trickle filter, and the water is routed horizontally. This is done by chambers separated by baffles to route the water. The first chamber is usually where you will put all your mechanical media. The second and the rest of the chambers, depending on how many, will be home to your biological media. The last chamber will be the holding area (much like the sump in a trickle filter), which holds the filtered water before it gets pumped back into your main tank.

But what about a sump filter above your tank? An overflow system will not work since we are fighting now the force of gravity. In this case, we can use a submersible pump inside the tank to pump out the water upwards and into your sump filter. The water pump’s power should be able to overcome the force of gravity, so make sure the height of your sump filter with respect to your submersible pump’s height is not too high.

For sump filters situated over your tank, you can just let the filtered water drain down into your main tank with the help of gravity, or you can channel the filtered water into a spray bay. The raining/draining water will further oxygenate the water. Sump filters positioned over your tank are designed that in the case of a power outage, the water will not drain completely due to the baffles design, keeping your filter media wet until the power comes back on.

How do I maintain a Sump filter?

Depending on your filter’s design and how you integrate easy access to an effective mechanical filtration, you will not be required to maintain your sump filter for a very long time and reducing the need for water changes. This means you only have to clean or replace your mechanical media and lets you leave your biological media alone for a long, long time.

To add to that, do not maintain/clean your filter/media with chlorinated tap water! Always see to it that you clean your filter media using old extracted water from a water change. Tap/chlorinated water can instantly kill the beneficial bacteria you have long-established. Your tank cycling reverts to zero. You will have the agony to repeat it (Hello cloudy water/bacterial bloom!!!).

Squeeze and rinse whatever mechanical media you have with old tank water only from a water change to release all the detritus, muck, organic matters trapped by it. Keep your biological media wet by submerging them, also in collected old tank water. Do not use foams, sponges, brushes, even your fingers, or any abrasive products to scrub them (your biological media). Just rinse them with old tank water.

What should I be aware of when using a Sump filter?

They are suitable for large to huge aquariums (50 gallons and up) (most often utilized with monster fish planted or non-planted tanks). But there are smaller tanks that have integrated sump filters as well (10 to 50 gallons). You can even DIY your tank with an integral sump filter (but that will take away space). There are many DIY designs and tutorials that you can research and implement all over the internet that will teach you to set up your very own sump filter using inexpensive materials. But really, no one can stop you from using an external sump filter for small to medium planted tanks. I have hobbyist friends that do.

By using a sump filter, it effectively adds more gallons of water to your system. More water means a more stable system. Any Ammonia spikes will likely go unnoticed, and you don’t have to follow the “1 inch per gallon” rule when it comes to stocking faunas. They are usually 1/3 the size of your main tank, but I know hobbyist friends that designed their sump filters equal or even larger than their main tanks. You can not put a larger sump filter than your main tank in terms of volume at the top for obvious reasons. 

Plus, you have a lot more room for your mechanical and biological media, but this means you have to spend more on media. Still, you can use cheap alternative media as a replacement to the commercial ones like lava rocks or pumice stones.

Setting up a sump filter for a beginner hobbyist might be restrictive due to the higher startup cost (available commercial models or customized ones). Not to mention you have to design the system well (DIY). However, considering a DIY sump filter requires careful planning and design in the event of a power outage to prevent overflow.

You can also set up your very own Aquaponics system with this filter. Aquaponics is a fusion of aquaculture, in which you grow fish and other aquatic animals, then Hydroponics, which is growing plants without soil. Aquaponics combines this symbiotic relationship in which plants get their nutrients from the aquatic animals’ wastes while plants serve as a natural filtration for the water for the aquatic animals’ benefits.

Depending on the size of your main tank, sump filters take up a lot of space, even though you can keep them hidden under your aquarium cabinet. There is little to no room anymore for your other equipment. A sump filter above your tank may rob you of some room/space to maneuver while working with your planted tank or doing maintenance. Did I not say that it causes distractions on an otherwise pleasant scape?

To summarize, here are the pros and cons of a Sump filter:

Below the Tank

Pros

  • provides excellent mechanical and biological filtration – plus you have a lot of room for your media
  • very customizable when it comes to the filter media of your choosing
  • Depending on your filter’s design and how you integrate easy access to an effective mechanical filtration, you will not be required to maintain your sump filter for a very long time and reducing the need for water changes. This means you only have to clean or replace your mechanical media and lets you leave your biological media alone for a long, long time.
  • can be completely hidden from view – you can also hide some of your equipment such as your heater from your main tank
  • ideal for heavy loads – you can get away with overstocking without affecting your water parameters
  • adds more water volume to your system – more gallons of water make for a more stable enclosed ecosystem for your faunas and plants. 
  • Completely customizable – you can design or buy customized ones according to your requirements.
  • Very flexible regarding main tank size – before, sump filters are only meant for huge tanks. But nowadays, they can also be very flexible with small to medium to large tanks.
  • It can be home to your very own Aquaponics system or a refugium. A refugium can allow you to home delicate fish/shrimp species or allow you to grow plants that can assist in nitrates reduction, such as Pothos plants (Epipremnum Aureum).

Cons

  • requires considerable planning and design to prevent flooding as a result of a power outage (if DIY) – this means you have to consider the size of your sump filter that is situated below your main tank to accommodate the extra water that will drain from your main tank (when holes are drilled as an overflow)
  • could be too overwhelming for a beginner in terms of cost (commercial models or customized ones plus the filter media) or when planning and designing (DIY)
  • takes up a lot of space even though you can keep it hidden under your aquarium cabinet
  • Unless you have an overflow box or DIY-ed your own overflow system, you have to drill the tank, which may not be appealing to some. Also, it isn’t easy to sell your drilled tanks in the second-hand market.

Overhead

Pros

  • can provide excellent mechanical and biological filtration
  • very customizable when it comes to the filter media of your choosing
  • Depending on your filter’s design and how you integrate easy access to an effective mechanical filtration, you will not be required to maintain your sump filter for a very long time and reducing the need for water changes. This means you only have to clean or replace your mechanical media and lets you leave your biological media alone for a long, long time.
  • Can return highly oxygenated filtered water – the draining of filtered water from an overhead sump into your main tank will create water surface agitation, which will oxygenate your water.
  • Ideal for heavy loads – you can get away with overstocking without affecting your water parameters
  • no need to plan for a power outage to prevent flooding – sump filters positioned over your tank are designed that, in the case of a power outage, the water will not drain completely due to the baffles design, keeping your filter media wet until the power comes back on.
  • can be home for your very own Aquaponics system – can grow terrestrial plants

Cons 

  • it causes distractions on an otherwise pleasant aquascape of the main tank
  • could be too overwhelming for a beginner in terms of cost (commercial models or customized) or when planning and designing (DIY)
  • may rob you of some room/space to maneuver while working with your planted tank from the top or doing maintenance
  • You must put a pump inside the main tank (another eyesore and equipment in the tank) to pump water into the overhead sump filter. The pump’s power and height of the sump filter is another concern making sure that the pump of your choosing can overcome the force of gravity.
  • Adds to the weight from the top of your main tank – limiting you only to use light-weight filter media – imagine the weight of a sump filter stuffed with filter media, full of water, adding more stress to your main tank’s structure.  

Stressing This Out Again!

Whichever filter you had chosen from the list above, do not maintain/clean your filter/media with chlorinated tap water! Always see to it that you clean your filter media using old extracted water from a water change or a water source known to have no chlorine. Tap/chlorinated water can instantly kill the beneficial bacteria you have long-established. Your tank cycling reverts to zero. You will have the agony to repeat it (Hello cloudy water/bacterial bloom!!!).

Squeeze and rinse whatever mechanical media you have with old tank water only from a water change to release all the detritus, muck, organic matters trapped by it. Keep your biological media wet by submerging them, also in collected old tank water. Do not use foams, sponges, brushes, even your fingers, or any abrasive products to scrub them (your biological media). Just rinse them with old tank water.

Conclusion

This article concluded the importance of a carefully chosen planted aquarium filter and how critical it is to support life in our tanks. It can distribute nutrients and CO2 across the whole tank and provides the water current that fish loves to swim against. It can also be a breeding ground for beneficial bacteria, provides the needed water surface agitation, oxygenating the water for our faunas, and nitrification activities.

Next are the Sump filters. A sump can provide filtration horizontally, opposite the Trickle filter, by employing chambers separated by baffles to route the water. It is designed that the media are always submerged in water instead of a Trickle filter in which the media is always exposed to air. A sump filter can be placed below your main tank, overhead, or integrated.

Maintenance, depending on your sump’s design and mechanical filtration effectiveness, will be very far apart. This means you only need to clean/change your mechanical media and don’t need to touch your biological media for a very long time. Before, they are more suitable for large to huge tanks, but nowadays, smaller tanks have integrated sump filters. 

There are many DIY designs and tutorials that you can research and implement all over the internet that will teach you to set up your very own sump filter using inexpensive materials and media. A sump filter effectively adds more gallons of water to your main tank. More water means a more stable system. They are usually 1/3 the size of your main tank, but there are implementations where the sump filter is larger than the main system. 

We also discussed the pros and cons of a sump filter for each: under and overhead. They might be too overwhelming to implement for beginner hobbyists, but the pros outweigh their cons (and some cons have alternatives or immediate workarounds).

Closing Remarks

I hope you enjoyed this article. If you have additional questions or want to share your experiences with the Sump Filters you used, please leave a comment below.

Next, we will be discussing the Fluidized Bed Filters.

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