Types of Planted Aquarium Filters – Trickle 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

Wet/Dry Filters/Trickle Filters

If you love DIY-ing, then you will feel at home on the next three types of filters that we will discuss, including this one. The trickle filter concept is to expose the water to as much air as possible, providing more dissolved oxygen. This will make your biological filtration very efficient and far better than other filters. If you can remember, your biological filtration’s efficiency in converting harmful substances (Ammonia and Nitrites) in your water into a less harmful form (Nitrate) depends on the amount of their food and oxygen in the water.

How does a Trickle filter work?

There are many designs for trickle filters. It consists of a tower, and usually, they are designed in conjunction with a sump. They can be below the main tank, hidden from view, and they can be over the tank. Whatever the design is, it always employs gravity force by letting the water drip/trickle-down/rain-down to the succeeding filtration stages below. 

It starts with some overflow system in your tank, letting the water overspill and channel to a drip plate. In some designs, if you so might be inclined, require drilling hole/s into your main tank at a certain height and plumbings to drain (overflow) the water into your trickle filter positioned below your main tank. When you think about an overflow, it is a mechanism that allows water to just flow out of the tank when it reaches a certain level. Think about how swimming pools or reservoirs maintain the water level by having holes in their side in a certain water level small enough not to suck in ‘people’ and swimming accessories.

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). 

In the case of a planted tank, the holes or gratings in your overflow system should be small enough not to suck in your fish. Once the water flows out of your main tank, it is collected and channeled into a drainpipe and then into your trickle filter tower with the help of gravity.  

A drip plate will be the first stage of your trickle filter tower and is some kind of container to hold the water with lots of holes drilled at the bottom. You can also put your mechanical media here. A drip plate will spread the water evenly and drip/trickle-down/rain down to the next stage below through the holes when appropriately designed. The next stage will be your biological media. As the water is being richly oxygenated by the action of trickling, your biological filtration works very efficiently. As the water trickle down further, it will arrive in a water-holding area called a ‘sump.’ 

The sump is just another tank or container that holds water. Usually, it is around 1/3 the size (in gallons) of your main tank. By employing a sump, it effectively adds more gallons of water to your system. More water means a more stable system, any Ammonia spike will likely go unnoticed, and you don’t have to follow the “1 inch per gallon” rule when it comes to stocking faunas. Another water pump in the sump will return the filtered water into your main tank, and then the cycle of filtration repeats.

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 and tune-ups.

But what about a trickle 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 trickle filter. The water pump’s power should be able to overcome the force of gravity so make sure the height of your trickle filter with respect to your submersible pump’s height is not too high, not to diminish the water flow too drastically. And if you are using a spray bar for a trickle filter with multiple columns, your pump should be able to pump the water until the last sections.

For trickle filters situated over your tank or pond, you can just let the filtered water rain down into your main tank or pond by drilling holes at the bottom sump. If you don’t want to drill holes in your bottom sump and want to control water flow, you can do this by employing a spray bar, channeling the water through it. The raining water will further oxygenate the water in your main tank or pond. Some people may feel relax with the sound of dripping water. Others may be annoyed.

Why are trickle filters also called wet/dry filters?

Some trickle filters have additional mechanical, biological, or even chemical filtration media put by the hobbyist in its sump part (if there’s any). Since they are submerged in water, this is the wet part. The tower part (drip plate, biological media) is above water and ‘dry’ (well, not really because the water is trickling down, but whatever. Some parts of a trickle filter are underwater (wet) and some parts above water (dry). That is why it is also called wet/dry filters. 

How do I maintain a Trickle filter?

The frequency of maintaining a trickle filter is very far apart, even as far as several months to a year. It depends on your filter’s design and how you integrate easy access to an effective mechanical filtration. 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.

If you don’t have an effective mechanical filtration in your design, you have to make sure that your biological filtration stage is not clogged by debris, preventing the water from trickling down on other paths (remember, water travels down with the least resistance paths). So periodically, you have to rinse off your bio-media to keep the passages from being clogged. The pumps and tubings will also need to be kept clean and free from accumulated slimy detritus. This hobby becomes a chore, so make sure to design your trickle filter’s mechanical filtration as effective as it can be and with easy access.

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 Trickle filter?

Trickle filters provide excellent biological filtration and effective mechanical filtration (depending on the design, as I mentioned above). They are suitable for large to huge aquariums (50 gallons and up) and ponds (most often utilized with monster fish planted or non-planted tanks), but there are smaller tanks that have integrated trickle filters as well (10 to 50 gallons). You can even DIY your tank with an integral trickle filter. 

It can be huge in design (it looks like an industrial water treatment system) and can serve as a centralized filtration for multiple tanks. 

Plus, you have 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 for the commercial ones.

Setting up a trickle filter for a beginner hobbyist might be restrictive due to the higher startup cost (available commercial models). Not to mention you have to design the system well (DIY). But there are many DIY tutorials nowadays all over the internet that will teach you in setting up your own trickle filter + sump using inexpensive materials (plastic containers as the sump/plastic organizers as the tower). Here is a great video example of designing your Trickle filter by Joey Mullen, also known as the King of DIY, on Youtube. 

However, considering a trickle 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, trickle filters complete with a sump take up a lot of space even though you can keep it hidden under your aquarium cabinet. There is little to no room anymore for your other equipment. A multiple-column trickle tower above your tank may rob you of some room/space to maneuver while working with your planted tank or doing maintenance. And where are you going to put your lights? Did I not say that it causes distractions on an otherwise pleasant scape? Some people might feel relaxed with the sound of dripping water. Others may be annoyed.

For a planted aquarium where you are injecting CO2, exposing the water to as much air as possible will waste a lot of your CO2 by degassing. This will make you compensate by increasing your injection rate, wasting more CO2 to achieve your desired dissolved CO2 levels for your plants. The trickling water will also increase your water evaporation rate.

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

Below the Tank with a Sump

Pros

  • provides excellent biological filtration
  • very customizable when it comes to the filter media of your choosing
  • frequency of maintenance can be very far apart and reducing the need for water changes – it depends on the design and providing easy access to your mechanical filtration. This means you only have to clean or replace your mechanical media due to the very effective biological filtration.
  • Can return highly oxygenated filtered water
  • 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 makes for a more stable enclosed ecosystem for your faunas and plants. 
  • Completely customizable – you can design and create your own trickle filter using inexpensive materials.
  • Very flexible regarding main tank size – before, trickle filters are only meant for huge tanks or as a central-filtration system for multiple tanks or a pond. But nowadays, they can also be very flexible with small to medium to large tanks.
  • It can be home for your very own Aquaponics system or a refugium in the sump part. 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 – 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 and when you used a sump)
  • the drip plate’s design is very critical for a very efficient biological filtration – when it is not designed well, it will have an uneven flow of trickling water into your biological media. Some media will not get even wet and you have a limited number of beneficial bacteria developing or can result in some die-offs.
  • could be too overwhelming for a beginner in terms of cost (commercial models plus the filter media or customized) or when planning and designing (DIY)
  • takes up a lot of space even though you can keep it hidden under your aquarium cabinet
  • for a planted aquarium where you are injecting CO2, exposing the water to as much air as possible will waste a lot of your CO2 by degassing.
  • 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

  • still can provide excellent biological filtration
  • very customizable when it comes to the filter media of your choosing
  • frequency of maintenance can be very far apart and reducing the need for water changes – it depends on the design and providing easy access to your mechanical filtration. This means you only have to clean or replace your mechanical media due to the very effective biological filtration.
  • can return highly oxygenated filtered water
  • ideal for heavy loads – you can get away with overstocking without affecting your water parameters
  • can provide low water current for your delicate faunas and still can provide excellent mechanical and biological filtration
  • no need to plan for a power outage to prevent flooding
  • can be home for your very own Aquaponics system – can grow terrestrial plants
  • the sound of dripping water into your main tank can be relaxing to some

Cons 

  • for a planted aquarium where you are injecting CO2, exposing the water to as much air as possible will waste a lot of your CO2 by degassing.
  • 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 plus the filter media or customized) or when planning and designing (DIY)
  • the drip plate’s design is very critical for a very efficient biological filtration – when it is not designed well, it will have an uneven flow of trickling water into your biological media. Some parts will not get even wet and you have a limited number of beneficial bacteria developing or can result in some die-offs.
  • may rob you of some room/space to maneuver while working with your planted tank from the top or doing maintenance
  • unnecessary consideration: where to put your lighting, ensuring that your main planted tank is lighted evenly, and your lighting will not get wet with all the water splashing happening.
  • the sound of dripping water can be pretty loud and annoying for some
  • does not add more water volume into your main tank as a sump does
  • You must put a pump inside the main tank (another eyesore and equipment in the tank) to pump water into the overhead trickle filter. The pump’s power is another concern making sure that the pump of your choosing can overcome the force of gravity and can pump the water until the last section of the spray bar of a multiple columned trickle filter.
  • 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 trickle filter stuffed with filter media and some 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.

The trickle filter is designed to expose the water to air as much as possible. Much further oxygenating it and thus will make your biological media very efficient and effective. It starts with an overflow system from your tank, routing the water to a drip plate, then to the tower, the sump (holding area), and then back to your tank.

There are many designs, and you have a lot of room for customizations. It can be placed under your tank and can be hidden, or it can be placed overhead the tank. Depending on the effectivity of the design of your mechanical filtration part, the frequency of maintenance is very far apart. 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.

Next, we also discussed the many pros and cons of each design. Whether the trickle filter is below your tank or overhead, both designs have distinctive pros and cons that will help you decide if this filter is the best for your situation. But as far as the most effective biological filtration is concerned, this filter can’t be beaten.

Closing Remarks

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

Next, we will be discussing the Sump Filters – wait, what? Did we already discuss that?

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