What is the Best filter for my Red-eared slider tank??

How important are filters to a red-eared slider tank?

The main purpose and function of an aquarium filter in your red-eared slider tank is to remove excess and unwanted materials such as leftover bits of food from your turtle’s messy eating habits, organic waste (poo) as well as chemicals – specifically those that are not beneficial in your red-eared slider living habitat.

Red-eared sliders excrete waste constantly throughout the entire day. This will result in build-ups of ammonia and other toxins that are very detrimental to the turtle’s well-being. If these unwanted wastes are not removed promptly, the ammonia will penetrate your red-eared slider’s body and will quickly build up to a fatal point, known as ammonia stress or ammonia poisoning.

Those little particulate floating in your turtle tank such as decaying food not only causes your water to turn cloudy, the bits of food will also start to rot and decay over time and release poisonous toxins if they are not dealt with.

The right filter makes a huge difference for your turtle

Having the correct aquarium filter for your red-eared slider turtle tank will make a big difference in terms how often you will need to change the water and clean the tank. Bear in mind that an aquarium filter touted to be the best for goldfishes might be even close to being suitable as a red-eared slider filter. As the needs of red-eared sliders and goldfish (or any other fish in that aspect) are vastly different. A turtle’s diet contains a much wider spectrum of food that includes live feeds from time to time. They are also a much messier eater and excrete a lot more waste than your typical aquarium fish.

Choosing the ideal type of aquarium filter for your red-eared slider turtle can be a daunting task because there are so many available options in the market, each having different specifications. All aquarium filters are designed with one specific purpose in mind of cleaning your water. However, there are many things to take into consideration before you buy one that is suitable.


What are the different functions of a turtle Tank Aquarium Filter

The functions are categorized into three distinct classifications. Each serves a different purpose, but are all equally important to keep the water in your turtle tank clean and clear. Any decent aquarium filter for your turtle MUST have the capability to fulfil all the 3 functions. Each of the functions is performed by the different media that will be housed in the filter. We will discuss the different type of media in the filter in the later part of the article. First, let us look at what are the different functions that the turtle tank aquarium filter should offer.


Mechanical Function

Mechanical filtration is the process whereby physical particles such as leftover food or solid wastes are removed from the water and trapped within your filter media when water is cycled through the filter,

It not uncommon to have little debris and particles in your turtle tank, red-eared sliders leave a huge mess as they feed, leaving lots of tiny excess leftover food floating around in the tank. There are also other forms of particles such as dust from the environment.

If left untreated, the water in your red-eared slider tank will soon start to turn cloudy. Mechanical filtration will purify the water and give your turtle a clean and clear tank. This will also promote good health for all animals in the tank.

Mechanical Media

Mechanical medias are the simplest and easiest to understand. The media traps all the debris and particulate waste such as solid wastes and leftover food scrimp when the water cycle through your filter.

Mechanical medias are categorized into 3 main types: filter pad, foam block, and filter floss. Filter pads and foam blocks serve the same purpose and can be mutually exclusive. They are usually the first level of defense and will catch on to slightly larger particles before the water eventually flows towards filter floss. Filter floss is much more refined compared to the larger pores of the filter pads and foam blocks to trap the finest particulate, ensuring that your water is crystal clear. You can always pack the filter floss tighter to sift through particles more effectively. However, if you pack your floss way too tight, water may end up not being passed through the floss resulting in the underlayer of biological media not receiving the required exposure to water for optimum bacteria colonization.

Another main difference between filter pad/foam blocks as compared to filter floss is that the latter is non-reusable. Filter pads and blocks can be easily washed by rinsing them with the water from your fish tank in a bucket. With that said, the cost of filter floss is very cheap and easily available.

Filter Pad

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Our Classic blue and white filter pad is a popular multipurpose filter media perfect for freshwater or saltwater aquariums. The filter pads’ resilient fibres trap floating debris to help keep your aquarium water crystal clear; the open fiber construction promotes water flow and prevents premature clogging. The Classic blue and white filter pad from Aquatic Experts is our preferred choice and its one of the most popular multipurpose filter media perfect for turtles. Its resilient fibers can trap floating debris to ensure the water in your turtle tank remains crystal clear; the open fiber construction helps promotes smooth water flow and prevents premature clogging.

These particular Pads are made out of very durable polyester fibers that are bonded by resin to give the media its exceptional strength. 

A good quality filter pad can trap food remains, wastes and other floating particulates from the flowing water. Changing your filter pads regularly will increase water quality of your red-eared slider tank.

Filter Floss

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When it comes to filter floss, the Blue Ribbon 100% Polyester Filter Floss is definitely our favorite! It consists of Soft, fine 100% polyester filtering fiber that is ideal for every type of filtration system. The blue ribbon filter floss is similar to that of pillow type stuffing where the fibers can be pulled apart with absolute ease. It is also very flexible in a sense that you can pack it however tight you want depending on how to trap medias of different fineness.

The best part of all, it is way a lot cheaper than many of the other prepacked mediums in the market!


Filter Foam

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There are many different filter foams in the market. Ranging from different shapes and sizes, but the majority of them are largely similar. But because of marketing and branding, the price range varies.. a lot! As far as mechanical filtration media goes, they have a very simple job. That is to trap physical particulate from the water. In our opinion, there isn’t really a need to go splurging too much money on mechanical media. The money would be better spent on getting a higher quality chemical and biological media, or better still, on a better filtration system.


With just a few dollars, you can get a pretty decent filtration foam that has great thickness and durability. This particular filtration foam measures at 50x50x2.5cm. That’s probably enough to last you a long time. Just cut out whatever you need to fit your filter, and stash the rest for future use. If you happen to change your filtration for some reason, the remaining blocks of the foam would not go wasted.


Chemical Function

Chemical filtration is the process of removing certain chemicals, discoloration, and odor from the tank. There are many various traces of chemicals present in our daily water, some of which may be harmful to aquatic life. One such example is hard metals.

occurs when toxic chemicals pass through a resin or media. Some chemical filtration products target specific excessive nutrients or chemicals from the aquarium. removing odors, discoloration, medications, and other chemicals.

When the water passes through the filtration system, it will interact with interact with the chemical media in the filter, thereby neutralizing or removing these chemicals. Bear in mind that under some circumstances, not only are harmful chemicals being removed from the water. Chemical filtration may also have an impact on medicines in the tank.

Chemical media

There are several different types of chemical media in the market. Carbon is the most common type of chemical media. Carbon is very effective at removing discoloration, odors, discoloration, and other chemicals. They do so by adsorption.  No, this is not a spelling error. Adsorption is the process whereby the carbon will ledge and stick onto certain chemicals. Once the chemicals are in contact with the carbon, they are “grabbed” and prevented from re-entering your water tank.

Bear in mind that not just the harmful chemicals are removed. Medications, trace elements, and micro-nutrients may also be absorbed by the carbon. Therefore, if you are going to treat a sick turtle with medications, you should remove all carbon in your filter before doing so. The carbon can be added back after the treatment is fully completed. The carbon will then remove any traces of leftover medication in the turtle tank. If you have a balanced planted tank, you probably don’t need to worry about carbon eliminating the “good chemicals” from your aquarium. More often than not, the use of carbon is beneficial to your overall tank community.

Remember to replace your carbon

Due to its adsorptive nature of carbon, they will usually be exhausted when its entire surface is coated in waste. Once the carbon is exhausted, it will need to be removed and replaced. It is really difficult to gauge the exact amount of time it takes for the carbon to be completely exhausted. A fairly common guideline would be to change the carbon in the tank anywhere from 4-6 weeks.

While carbon does a great job at removing certain harmful chemicals from your red-eared slider tank, there are still some notable toxins where no amount of carbon will make an impact. For instances: Ammonia, nitrites, and nitrates are not affected by carbon. The removal of the above substances would have to be through biological filtration as well as frequent water changes.


Marineland Black Diamond Premium Activated Carbon

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The Black diamond premium activated carbon does a great job of eliminating discoloration, impurities, and odors. This particular type of activated carbon works faster and then last for much longer compared to the brands in the market. Each bit of carbon is activated via heat with bituminous coal-based black diamond granules. Bituminous activated carbons are way efficient compared to others such as coconut, wood or peat-based activation.

The Marineland black diamond carbon does wonders in keeping the water in your turtle tank sparkling. Besides that, one of the main reason this is our preferred carbon is due to its moisture presence (or lack of). The concentration of carbon in the Black diamond carbon is significantly due to its low moisture concentration. This means that for a 40oz bottle, the Marineland black diamond carbon can work as long as 100 oz of carbon from its competition. Talk about value for money!

Marineland Diamond Blend Ammonia Neutralizing crystals

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The Marineland White diamond blend works its magic by absorbing of ammonia and chloramines. Although biological filtration will also aid in nitrifying ammonia, it does so by converting it to nitrites and nitrates, which is still not 100% beneficial to your turtle. We will discuss this more in the next section. The Marineland white crystals increase the amount of ammonia absorbed, sharing the workload of its biological counterpart, thereby extending the time between water changes. Together with the black diamond, This amazing combination will do wonders for cleaning and condition the water in your red-eared slider tank, ridding it of organic waste and odors by removing toxic ammonia and chloramines.


Biological Function

Biological filtration is the breaking down of various bacteria in your red-eared slider tank.  This process is known as the nitrogen cycle.

The nitrogen cycle is the process where ammonia produced by your red-eared slider throughout their daily activities as well as leftover food bits are converted into Nitrite, and then to Nitrite.

Ammonia is extremely to all aquatic animals even in low concentrations. Hence, the biological filtration process is vital to the health of your turtle. In order to do that, you will need to establish a thriving bacteria colony that can effective cycle through the ammonia into Nitrite and Nitrate

What is the difference between Nitrite & Nitrate??


When the colonized bacteria eat up the ammonia, Nitrites are produced. Just like ammonia, Nitrites is also very toxic to aquatic life like turtles. They compete with other organisms in the tank community with oxygen. While turtles can breathe on land, nitrites can be detrimental to other lifeforms just at water plants and plankton. Nitrate will also affect the blood of the red-eared slider’s ability to carry oxygen.

ammonia-eating bacteria, and are also highly toxic to fish. Like the cycling in step one, you must build up enough nitrites to form a second colony of bacteria that will dispose of them as they are produced. These bacteria will, in turn, create nitrate. Once your levels of nitrites AND ammonia have reached 0ppm (“parts per million”), your tank is said to have been cycled.


Nitrates, on the other hand, are the final result of the nitrogen cycle. As Nitrites builds up in the water, A 2nd bacteria community will eat up the nitrites and produces nitrates. Unlike nitrites, nitrates are not as toxic to aquatic life, as long as they are kept in low concentration. Too high concentration of nitrates can still be detrimental to your turtle’s health. So even with the biological filtration that gets rid of the most harmful ammonia, a partial change of water in your turtle tank from time to time is still required.


Biological media

Biological media, AKA bio-media provides a platform to house nitrifying bacteria community. One of the most common types of bio media is ceramic rings. Ceramic rings’ extremely porous nature creates a massive surface area to colonize bacteria effectively on and inside each ring. The following design also allows maximum distribution of water flow. Ceramic rings are fully submerged for the whole surface area to be in contact with the water, allowing effective colonization of beneficial bacteria.

Another common bio media that you will see would be bio balls. Bio balls are mainly designed to be housed in trickle wet/dry filters where water will flow through the balls instead of being fully submerged. Although bio balls are larger in footprint, they offer a much small surface area to colonize bacteria. However, the lack of surface area of bio balls is made up for by the great air to water interaction that allows the bacteria colony to thrive much more effectively.

One complaint of bio balls, however, is that they tend to trap debris, which tends to rot and produce ammonia if they are not removed. This is often due to improper placement order of your filtration media. The bio balls should always be after your mechanical media. This meant that any water that comes into contact with the bio balls would have already passed through the filter pads or filter floss to remove all debris.

Mixture bag of ceramic rings & Bio balls at a great price!!

We’ve just have discussed on the pros and cons of each biological media. You must be thinking right now, wouldn’t it be nice to be able to enjoy the benefits of both bio balls and ceramic rings without spending too much money and buy both?


Well, here you have it! For a great price, you can get a mixture of both ceramic rings and Bio balls together! With this, you will get to enjoy the porous and massive surface area of ceramic rings for colonization, and also great air to water exposure for the bacteria colony to thrive effectively!



How do I choose the right filter for my red-eared slider?

There are several considerations you will want to keep in mind when you are choosing a filtration system ideal for your red-eared slider tank. Choosing an unsuitable or wrong filter can be very troublesome and a waste of money.

The Filtration Technology

The first on the list will be filtration technology. As mentioned earlier, the 3 main filtration function is mechanical, biological and chemical. A good filter for red-eared slider must be able to perform all 3 function satisfyingly. This is very important as red-eared sliders are known to produce a lot more waste and mess than much other aquatic life. If your filter does not perform either function properly, you may have to end up spending extra money for a supplementary filter.

Turtle Tank Size & type

It is very important to understand that not all type of filter will work and fit well with all tanks. For example, if you have one of those all in one aquarium like the Red Sea 23439 Reefer X-Large 525 Rimless Reef-Ready Aquarium System that has a built-in cover as lighting, a hanging or overhead filter is not going to fit. With that said, the Redsea max also has a built-in filter that covers all 3 aspects of a filtration system. But in certain circumstances, you may need to have a secondary filter on top of the built-in filtration system. So, you will have to bear that in mind.

Apart from the type of filter, the red-eared slider tank size will also need to be considered. A bigger turtle tank will mean a higher water volume. A more powerful filter is required so that all the water can be circulated more effectively. To determine how effectively the filter can circulate water, you will need to look at the flow rate.


Water-Flow Rate for The Filter

The water flow rate of the filter is measured in gallons per hour (GPH). This measurement represents the maximum number of gallons of water can pass through the filter in an hour. Filter flow rate will determine how efficient water movement throughout the aquarium.

The flow-rate of a filter can usually be identified by the label on the filter box. The label would usually come with a recommendation on what tank size the filter is most suited for. Point to note, the recommendations are usually meant for an aquarium that keeps fishes. Red-eared sliders are much messier compared to goldfishes. So, you should get a filter with water flow rate that is meant for a bigger tank.


Size and population of your red-eared slider

The population size of your red-eared slider community is very important. An aquarium with multiple turtles will subject your filtration system to much more stress. Hence, a bigger and more power filter will be required, or even a secondary filter to share the load.

Adult red-eared sliders will also eat more food and naturally produce more wastes than hatching turtles. Hence a more powerful filter with higher flow rate would be preferred for bigger turtles. While a smaller hang on back filter may be enough for your current baby slider, that same filter is not going to cut it as your turtle matures. You will need to factor in the cost to buy a new filter if you are using a smaller system now.


Space is something that many people overlook when they are picking a new filtration system for their red-eared slider. Canisters and wet/dry filters are great for red-eared sliders. But they also take up the most real-estate. This is due to their housing capacity for a large amount of media. Be sure to clear up and make some calculations to allocate space for not just your filter, but for every piece of equipment that you will need before you proceed to set up your aquarium.


Brand of the red-eared slider filter

We are not trying to be brand conscious here. But there is a reason why certain brands are much more well-known and popular in the market. Well, advertising and heavy marketing may play a part. But ultimately, the main reason these brands thrive compared to others has to be quality. Only by ensuring top quality in the products they offer, can the brand be able to sustain its reputation. Having a good quality filter will also ensure that the filtration system for your turtle tank works all the time. Remember, red-eared sliders create a lot of mess and waste. You can’t really afford to have a low-quality filter that breaks down all the time.

By no means are we saying that companies that are less reputable produce lower quality goods. However, if it is too much trouble for you to conduct such in-depth researches and comparison, it is much safer to go with a reputable brand.

Online reviews of the Filters

A good way to know if a filter manufacturer is reputable is through online reviews. There are many online communities on aquarium discussion. You don’t necessarily have to limit yourself to red-eared slider discussions. You can also check out other communities like larger freshwater fish forums to see what are the recommendations by fellow aquarium fanatics. Otherwise, you can always check out the review section of the Amazon listing of the item.

Any filter review will help to identify a good fish tank filter that you need for your aquarium. Some filter manufacturers might exaggerate the filter features that do not end up meeting the user needs. From the reviews, you can know more about the filter and decide whether it works for you or not. Some of the users of such filters will offer the useful information of helping other users to identify the best filters in the market. Make sure that you read the reviews from top rated stores and review sites as a way of finding honest reviews about the products.


Which type of filter should I get for my turtle?

There are many different types of filters in the market available. However, not all the filters are equipped with the capability to meet the needs of red-eared sliders. Let’s discuss what are the different type and whether it is suitable for the red-eared slider.

Air-driven internal fish tank filter

Air-driven internal fish tank filter is filters that are totally submerged into your red-eared slider tank. These kinds of filters are usually small and compact, making it ideal for small and Nano aquarium. Some of these filters may require an air pump and airline to produce the required water movement through the filtration system.

While they may be perfect for goldfishes and guppies, it is definitely not enough for an adult red-eared slider turtle as most of them tend to have smaller flow rate. Small internal filters usually only have mechanical filtration function with only one small compartment for a tiny sponge.

Disadvantages of internal filter

The main disadvantage of using an internal filter is the maintenance. The filtration system is usually attached to the tank with strong suction pads, which is not really easy to remove. Also, when you try to take out the filter to wash the sponge, some of the filter scums will flow out back into the water, turning your water very cloudy. Although these scums will eventually be cleared soon after you place your filter back in. Also, sticking your hand inside to fiddle with the filter will cause unnecessary stress on your turtle.

Internal filters also take up significant swimming space for your red-eared slider turtle. This could be a problem if your tank is not as big.

If you are starting out with a baby slider with cost constraint, the internal filter is the perfect alternative. However, you will eventually need to upgrade to a stronger filter and bigger tank as your turtle matures. The internal filter can always be fitted in your bigger tank as a secondary filter to share some of the load of your main filter.


    1. Ca 900 Internal Aquarium Filter (Most Value for money)

The Ca 900 Internal filter tops our list for the most value for money internal filter. This is an inexpensive filter, good option up to gallon tank for your young turtle

The Ca900 internal filter has a very decent Output of 235 GPH (Gallons Per Hour) and will work with up to 50-gallon aquariums for your red-eared slider.

The installation is relatively easy. All you have to do is to just place the whole unit submerged in the water. Then,  mount the filter to any surface tank using the suction cups attached to the back.

It also comes with a washable sponge with 2 sponge holders. You will have the option to insert some media bags in between.

The most important point here is the price point. For such an incredible price, this is probably one of the best internal filters that you can get!

The Aqueon Quietflow internal filter is another fully submersible internal filter. As the name suggests, this is one of the quietest internal filtration systems in the market. The motor sound of internal filters is a very common complaint amongst users, this problem is non-existent with the Aqueon Quietflow. This internal filter has an adjustable direction and height water output to ensure minimal disruptions in your tank.

Something that you wouldn’t find in many entry-level internal filters would be multistage filtration. Not the Aqueon Quietflow. This filter comes with an impressive Three stage filtration! With the first stage consisting of dense foam to trap particles and debris, a second activated carbon for toxins, odors, and discoloration. And last but not least, it uses a  patented BioGrid to effectively reduce ammonia and nitrates in your turtle tank.

With a flow rate of 155 GPH, it is suited for turtle tanks of up to 40 gallons. Another point we like about the Aqueon Quietflow internal filter is its sleek and low-profile design that allows you to count it either horizontally or vertically and it will work just fine.

Here comes the powerhouse of internal filters! If you have a bigger turtle tank which requires a more powerful filter, the Marineland Magnum Polishing Internal Canister Filter is just what you want!

Pumping an impressive 290 GPH, the Marineland Magnum internal canister filter is suitable for tanks of up to 100 gallons.

The unit houses 2 refillable chambers for activated carbon or any customizable filter media of your choice. The Marineland Magnum Filter also adopts powerful three-stage filtration system to effectively clean and polish your red-eared slider’s water.

The mechanical portion uses a Rite-Size floss sleeve traps tiny dirt and debris. Chemical filtration to removes odors, discoloration, and water impurities. (did we mention it comes with black diamond carbon? How awesome is that?!) And the other chamber provides an impressive 153 square inches surface area for the growth of Bio Spira. Bio Spira is a beneficial bacterium that helps neutralizes ammonia and nitrites.

The Marineland Magnum also polishes your water with its reusable pleated micron cartridge efficiently. The process is great at removing fine debris, leaving crystal clear water in your turtle tank.


Under gravel filters

Under gravel filters are filters that are fitted at the bottom of the turtle tank, with a layer of aquarium gravel underneath. The water will be sucked through the gravel through the uplift tubes with the use of an airstone with an air pump. You can also use a powerhead for this purpose.

The movement of water through the gravel will simulate biological filtration process where the bacteria colony will break down ammonia and nitrites into nitrates.

Under gravel filter are mainly used for biological filtration. They do not do a good job for mechanical filtration for remove particles from the water. Those wastes will usually be trapped within the gravel. Red-eared sliders are known to dig through gravels. When they do so, any trapped debris may be stirred up and trigger a spike in ammonia levels and hydrogen sulfide.

Under gravel filters also do not make the mark when it comes to chemical filtration. Sure, you can use replaceable cartridges that contain activated carbon to help with the chemical filtration. However, it is usually not enough and difficult to replace.

Under gravel filters, like the internal filter is great as a secondary filter for biological filtration. However, it should not be solely relied on as your only filtration system in your red-eared slider tank.


Penn Plax 40/55 Gallon Aquarium Premium undergravel filter (Best value for Money)

The Penn Plax premium undergravel filter is a great option to set up a biological filter for your red-eared slider tank.

The 40/55 size fit our 55-gallon tank great. It comes with 4 plates with each plate having two tube attachments. The inlet holes of the plates have the same grid work as the plates. That means the gravel will not easily fall underneath the plates due to the removal of powerhead or tubes. It also comes with clips to hold the sections in place along with channels to allow smooth water flow under the filter.





Lee’s 40/55 premium undergravel filter ( Best Performance)

At a slightly higher end of the price spectrum, we have Lee’s 40/55 premium undergravel filter.

The larger plate sizes of the Lee’s UG filter reduces the number of plates required. It is also comparatively stronger as it uses a higher quality plastic bedding compared to the PennPlax model. There are a total of 4 outlets on each plate. Each outlet has 4 tubes and 4 covers to close holes that are not utilized.

The Lee’s undergravel works great with a good power filter such as the Odyssea EX 250 powerhead.

This will help to keep your turtle tank in good and balanced pH with crystal clear water



Hang on back (HOB) / power filters

HOB filters or power filters is another common type of filtration system widely used in many aquariums. The system hangs on the back of your turtle tank.

It provides effective filtration and the outflow of the water are usually near the water surface to provide oxygenation. They are easy to set up and is very durable. Many people love them, as they provide the effective filtration for biological, mechanical, and chemical.

HOB filters are pretty compact and hence they do not take much space inside the tank apart from the water input tube. There is also good surface agitation to prevent the water from becoming too stagnant and promotes good water circulation because of the water flowing in from the top of the water surface.

The disadvantage of hang-on-back filters thou is that the compartment to house the filter media is quite limited. This meant that there may not be enough space to house bio media to form a large enough bacteria colony to effectively neutralize all ammonia and nitrites in your turtle tank.

Most of the power filters in the market has specific filter cartridges that meant for specific models. These cartridges and sponges can be easily rinsed as and when debris build up or when you are doing a water change. However, they ultimately need to be replaced and this will be an ongoing cost. Model-specific cartridges and foam are also usually most costly than generic ones. Also, as the cartridges and filter pads are small, they are subjected to wear much more easily than one that has a larger surface area.

  1. Marineland penguin power filter (Most Powerful)

The Marineland penguin power filter is probably one of the most effective Hang-On-Back filters out there. It has a certified flow rate of 350Gallons Per Hour, which makes it ideal for turtle tanks of up to 70-gallon. The Penguin utilizes two Rite-Size C” filter cartridges that deliver a 3 stage filtration.

It does a superior job in handling bio-loads of your red-eared slider turtles with its patented BIO-Wheel design.

The BIO-wheel allows beneficial bacteria required for biological filtration to thrive. This has been proven best at ridding ammonia and nitrites. There is also a noise reducing cover that makes this filter even more convenient and enjoyable for both you and your turtles. This type of 3-stage system will guarantee that your aquatic environment thrives to its highest ability.

The Marineland penguin has the ability to use up to 4 cartridges at once.

Fluval C4power filter (Most efficient filtration)

The main highlight of the Fluval C4 power filter will be its very impressive 5 stage filtration. It is wonderful for turtle tanks of up to 70 gallons. The output flow of this filter is 264 gallons per hour, which is considerably lower than the Marineland penguin. It is intentionally built that way to provide a more gentle flow, causing minimal disturbance to your turtle without any compromise on filtration effectiveness. The reduced flow rate also allows the water to be re-processed multiple times for a sparkling clean water. Not to mention it is also more power saving.

The Fluval C4 is well engineered to grant you superior water quality with the 5-stage filtration. The Fluval C4 is designed to give you maximum surface area and dwell time for a clear and healthy water for your red-eared slider turtle.

Aqueon QuietFlow LED PRO Aquarium Power Filters (Quietest)

The Aqueon Quietflow power filter is our top pick for the most value for money HcOB filter.

The whole filtration system is designed to include unique features that enhance water quality and clarity. Not only does the whole setup allow increased oxygen levels, it is also one of the quietest power filters we’ve seen. The Aqueon QuietFlow Power Filters has four stages of filtration. Being mechanical, whereby the particles and debris are removed. Followed by Chemical filtration that removes toxins, odors and discoloration using activated carbon. Biological filtration using the patented Bio-Holster that effectively removes toxic ammonia and nitrites. Finally, the water will flow through a diffuser grid which removes remaining toxins. This is done while inducing oxygen to your turtle tank. The grid also reduces splashing which is what the Quietflow is so exceptionally quiet.

The internal pump design of the filtration system also helps dampen noise and eliminates leaks.


Canister filters

Canister filters are perhaps the most popular type of filters used by red-eared slider enthusiasts. These are excellent for tanks 40 gallons or more. Canister filters cover all aspects of a good filtration system. They offer exceptional mechanical, chemical and biological filtration. The housing tank is known as the canister, are also larger than most hanging filters on the market.

Due to the large chamber of the canister filter, the total water volume in your whole aquarium ecosystem is increased. The Higher volume of water reduces the concentration of ammonia and other toxins. The PH will also be more stable as a result of higher water volume.

Not only is the water volume increased, having the whole canister outside of your turtle tank reduces clutter in the turtle’s living habitat. There are more swimming space and less obstruction for your red-eared slider turtle to swim around.

Also, as compared to hanging filters that rely on the law of gravity for the flow of water through the media, Canister filters are enclosed and pressurized which means water is forced through the filter pads, thereby making a more effective overall filtration.

The disadvantage of a canister filter, however, would be maintenance. In a full-fledged canister filtration system, there will be various compartments and chambers for baskets, cartridges, media bags and various foams and paddings. All these will need to be taken apart for cleaning during maintenance.

Although the canister filter may require more effort setting up and maintenance, the power and flexibility it offers is definitely a good trade-off.

Penn Plax 1000 Cascade Canister Aquarium Filter (Most popular choice)

The Penn Plax Cascade Canister Filter is an exceptionally heavy-duty canister filtration system. This filtration system is ideal for turtle tanks of up to 100 gallons. It pumps more than 265 gallons per hour and delivers the most powerful mechanical, chemical, and biological filtration.

With The Penn Plax Cascade Canister Filter, you are guaranteed the highest quality crystal clear water for your red-eared sliders.

The construction of this filter is very sturdy with all the components of the made out of very high quality and durable plastic. It is much stiffer and stronger than the many of its competitors.
The Penn Plax cascade canister filter has 5 filter baskets that are all spacious enough to fit in various filtration media of your choice. With so much space, you will be spoilt for options. We love the fact that the package comes with both a spray-bar and spout outlet which allows you full customization.

Flexzion Sun Sun Canister Filter 304 (525GPH) (Enhanced UV sterilizer)

The Flexzion Sun Sun canister filter works best for tanks of around 150 gallons. It features a very high water pressure and very strong powered pump that pumps an amazing 525 Gallons of water per hour, making it the most powerful and highest workload canister filter in our list.

The water in your turtle tank is fed into the canister for a double filtration 3 media trays that are more than capable of handling all types of filtration methods. It also Comes with an adjustable spray bar that lets you adjust the output flow to your liking.

The Fkexzion Sunsun canister filter provides superior filtration ideal for heavily-stocked tanks. We also love the fact that there is a UV sterilizer function. The UV sterilizer helps sterilize the water in your turtle tank.

Fluval Canister Filter, FX6 Filter (400 Gal) (If you have a really Huge tank or Pond)

When we talk about the Fluval FX6, we mean its really for huge tanks. This super capacity yet compact canister filter can pump a superb output of 925 gallons of water per hour and has a filter circulation of 563 GPH. This is easily the highest work rate filter that we have!

The Fluval FX6 is a Multi-Stage Filter that produces top quality aquarium water for your turtle tank! This filter features a Smart Pump Technology for which makes use of an advanced electronic circuit board to continually monitors the pump for top filter performance, efficiency, and management. It is also Self-starting systems whereby additional air buildups in the system is evacuated automatically. You just have refill additional water and there will be plug-in Built with a maintenance reminder. For aquariums up to 400 gallons

Filtering media can easily be fitted into the several media baskets which are very easily assessable. The baskets are precision-engineered to eliminate all water by-pass, making filtration very efficient.

At only 21″ in height, the Fluval FX6 is a small package that packs an amazing punch!


Overhead filter

Overhead filters are similar to a HOB filter. The main difference is that instead of a small filtration system that hangs at the back of your turtle tank, the overhead filter seats right on top and span throughout the whole length of your tank. The only part that will be submerged in the water would be the powerhead to pump water into the filter box that houses all your filter media.  Water pumped up to the housing compartment by the powerhead will flow past the filter media in the compartment and back to the tank via gravity.

Overhead filter vs HOB filter

Compared to a HOB filter, the housing compartment for filter media is much bigger for you to fit in any filtration media. This allows more media to share the load more evenly and hence last much longer. The big filter compartment also let you carry out maintenance work without having to turn off the water pump. The lid can be opened to replace or clean your foam with minimum disturbance to your turtle.

The filtration system of the overhead filter also provides great air to water interaction that allows the bacteria colony in your bio media to thrive. They also provide excellent water circulation better than the HOB filter as under a typical overhead filter setup, water is fed through the powerhead into the housing compartment from one side of the tank and back into the back through the other end. This prevents the filter from picking up water that has just re-entered the tank.

However, because of the placement of the overhead filter, it may be a problem if there you use a lid to cover your turtle tank. It also takes up a lot of real estates where lightings for the tank should be. So, if you are considering an overhead filter, ensure that the placing of the filter will not be a hindrance to you.


Wet/Dry filters

Wet/dry filters, also known as trickle filters has the utmost performance in terms of biological filtration. The filter gets its name from the trickling of water through the various bio media instead. As mentioned previously, air and water exposure is the optimum condition for the bacteria colony to thrive. It is much more effective compared to having the bio media soaked in water inside an enclosed housing. This meant that these filters do the best job in breaking down and removal of ammonia and other toxic waste.

These types of filters also require the most of the space to house large amounts of bio media such as ceramic rings or bio balls. This also meant that the wet/dry allows you to have an even higher volume of water in your tank, which is great for lowering the concentration of ammonia build-ups in your turtle tank.

DIY wet/dry filtration system

There are many turtle fanatics who DIY their own wet/dry filtration system, which is amazing. When making your own wet/dry filtration system, bear in mind that is ALOT of hard work involved. However, it is a lot of fun and you are probably limited only by your own imagination. Some of the most common methods are using a separate fish tank, or even a plastic tower cabinet like this one.

If it is too much hassle to make your own or gather all the different parts, you can always order one on the internet and have it delivered to your doorstep.

Wet/dry filters are mainly designed and used for saltwater aquariums that demand a very high level of biological filtration. If the population in your turtle tank is not that big, a big wet/dry filtration system may perhaps be an overkill. A decent canister or overhead filter will probably be good enough to satisfy your red-eared sliders needs.


AE SHOP Aquarium Filter Fish Tank Upper Trickle Box Filters System

The AE SHOP wet-dry filtration comes in form of an overhead filtration that allows water to trickle down the different layers, achieving the most effective biological filtration. It is designed to fit turtle tanks of up a 100 gallons. This filtration system can handle powerhead of up to 1000 GPH.

This filtration system is a series of stacked trays to house various filter media that you would prefer. Water is sucked up to the top tray using a powerhead and trickles down throughout your filter tray. This makes the whole system very customizable as you can set the tank up however way you desire. We would recommend that you have at least 3 layers to satisfy all physical, chemical & biological filtration.

Also, as this is a trickle design filter, your biological media will have very good exposure to oxygen. This allows the bacteria colony to thrive very effectively, ensuring top-level biological filtration. So this filter is very useful have you have several turtles in the tank with a higher bioload.


In that order should I place my filter media?

You may have the most power and high-quality filtration system that money can buy. But if the order of your filter media is out of place, even the best filter will not be able to perform effectively.

While the impact of an improper order of filter media may not be visible immediately, it should not be overlooked.

The very first layer of the filtration media should always be the mechanical media such as filter pads and filter floss. This is because physical wastes and particulate should be filtered off before the water interacts with your chemical and biological media. If these particles are not removed, it may be stuck onto your bio or chemical media. When the particles start to rot over time, it will increase the ammonia and toxic concentration.

The order of mechanical media should also be from coarsest to finest.

This is to trap away larger particulates with the larger pores padding before the water eventually flow to the finer filter floss to remove any left-over substances. Filter pads and foams are not disposable and can be washed and reused. Whereas filter floss is disposable and needs to be replaced when it gets dirty. Arranging your mechanical media in such order will reduce the frequency of having to replace filter floss. While filter floss is very cheap and easily available, every penny saved is a penny earned.

When it comes to placement of chemical and biological media, we don’t really see much difference either way. However, if you are using more than one type of chemical media, you should probably arrange your media in such a way that the water will reach the most basic chemical media such as activated carbon first, before eventually flowing to more specific chemical media like Purigen of GFO. This allows your carbon to absorp whatever it can first before letting the latter to effectively target specific chemicals.

Chemical media will do no effect to ammonia, nitrites, and nitrates. Similarly, Bio medias will have no impact on most of the chemicals. Arranging them either ways will probably make not much difference. Whichever way you arrange these media, the water should be allowed to flow through smoothly and evenly across all the media. This will ensure that all the media will be able to be in contact with the water.