Filtration in aquariums is a very important process for cleaning and good quality. Thanks to well-cleaned and filtered water, fish can live in good condition. In this case, we are going to talk about a material that helps increase the performance of water filtration in aquariums. It is about zeoliteZeolite is a filter substrate whose performance in the water filtration process is superior to that obtained with activated carbon or sand filters. Furthermore, it is a product of natural origin.
If you would like to know how zeolite is used and the requirements you need, in this post you can find out everything in depth
Zeolite characteristics
The structure of zeolite is formed by minerals that come from volcanic structures. It is composed of minerals and crystals of a high ion exchange capacity (cation exchange). If we analyze the internal structure of this material, we can observe small channels of about 0,5 nm in diameter. This makes it considered a porous material suitable for water filtrationThis way, you can remove any dirt that may be in suspension from the water, keeping the aquarium completely clean.
The structure is completed with several parts that contain some larger diameter pores. It is really this ion exchange capacity that makes the adsorption of dissolved compounds present in the water and possible filtration. In simple terms, the pores and their charge accommodate ions of sodium and potassium which are exchanged for ammonium ions when water passes through the material.
There are several types of zeolite. Depending on the type we are treating, it is possible to extract the water from certain minerals such as calcium. This allows the hardness of the water to gradually soften and increase its quality. On the other hand, pores that are larger They are capable of retaining suspended particlesMany of these particles are organic elements and molecules, such as ammonia, and can reduce water quality.
At the compositional level, zeolite is mainly made up of silicon and aluminum in a microporous crystalline mesh, with other elements such as sodium, potassium, iron and magnesium in its structure. Among the most commonly used zeolites in aquariophilicity is clinoptilolite In freshwater, it is very effective at exchanging ammonium (NH4+). Specific mixtures and synthetic zeolites optimized for specific purposes are also available.
In addition to its chemical effect, some commercial presentations of activated natural zeolite offer a fine mechanical action, capable of helping to retain solid particles down to a few microns, leaving the water especially clear. These presentations are sold in different granulometries (e.g. 1–2,5 mm; 2–5 mm; 4–8 mm; 8–16 mm), allowing the flow rate and contact surface area to be adjusted to each filter.
How Does It Work?
Once we know the characteristics of zeolite, let's move on to how it works. Remember that it is a substrate capable of exchanging ammonia and that it works differently in freshwater or saltwater. It's important to understand the function of zeolite depending on the type of aquarium you're going to have.
Zeolites that are calcium exchangers They are capable of adsorbing ammonia compounds present in the low presence of calcium and magnesium ions. This occurs in freshwater aquariums. In practical terms, clinoptilolite removes NH4+ from the water and in return releases ions such as sodium or potassium, an exchange that It is not usually a problem in normal concentrations. As a side effect, it may contribute to a slight softening of water by trapping calcium and magnesium.
On the other hand, if we choose a seawater aquarium, the process is totally different. In this type of water, the presence of calcium is much higher than in fresh water. Therefore, the zeolite in this medium acts as a microporous biological substrate. Furthermore, numerous bacteria can concentrate on the surface, rapidly transforming ammonia into nitrite, and this into nitrate. In this case, the interior of the zeolite has a very low oxygen concentration. This is due to the high oxygen consumption on the outside. Therefore, the bacteria that settle in these areas are completely autotrophic and capable of synthesizing their own food. They also eliminate nitrate, transforming it into evaporable nitrogen with the help of oxygen. organic carbon available.
When zeolite is used in high performance marine systems, it is often integrated into a specific reactor: Water flow is controlled through the bed, and the load is agitated 1–2 times a day. This agitation loosens dust and biofilm from the surface, preventing pore collapse. improving skimmer performance and providing fine particles that can serve as food for sessile invertebrates. The commercial mixture ZEOvit, for example, is a balanced combination of different zeolites designed for this use.
It is convenient to understand that, in marine, the usable carbon For bacteria, water is a limited resource. If it is not provided or managed properly, the system will tend to nitrify rather than denitrify. Therefore, many methods combine zeolite with bacterial cultures and a carbon source carefully dosed.
Maintenance and requirements
Zeolite is not infinite, but it degrades over time and loses its effectiveness. This is because the bacterial colonies are reproducing to the point of clogging the pores of the surfaceWith clogged pores, their filtration capacity is reduced to the point where they can no longer perform their function.
This is why zeolite requires maintenance. Once it begins to fail in the water filtration process, it must be replaced. During the last effective phase of loading, massification of bacteria improves the performance of skimmer larger masses of debris detach from the surface and are rapidly removed by the marine debris.
When zeolite is used in an aquarium to aid in filtration It is recommended to use it graduallyThat is, you should never start filtering water with a full zeolite charge. This is because its water-filtering capacity can affect fish that are already adapted to certain aquarium conditions.
All zeolite manufacturers recommend installing it gradually, over a period of weeks, so that the fish can adapt to the new water quality. As time passes after installing zeolite in the aquarium, the bacteria become extremely active. When their activity reaches its highest levels, can impair the redox potential of the aquarium due to the high oxygen consumption, so it is advisable to ensure good aeration and skimming.
In addition to periodic replacement, there are practical guidelines that improve the result:
- Mechanical prefiltering: Place the zeolite after a sponge/perlon stage to prevent it from becoming saturated with particles and quickly losing effectiveness.
- Placement: in fine mesh bags inside the filter (canister, backpack, box) or in zeolite reactors with upward flow in marine.
- Agitation In reactors: 1–2 times a day to loosen debris and reactivate the surface.
- Flow in ZEOvit type mixing reactors: around 400 l/h per litre of zeolite, with Dosage approx. 1 L per 400 L of water; replacement of the load every 6–8 weeks.
- Standard dosage in bag: For reference, Seachem Zeolite type products are used at a rate of 250 ml per 200 L of water, checking ammonia every 24–48 hours.
Monitor with ammonia tests, which should drop to zero within 24–48 hours when used in freshwater with ammonia present. At that point, depending on the purpose, you can remove the zeolite or replace it with activated carbon. To maintain heavy metals some brands recommend keeping the zeolite in service and changing it monthly.
When you should NOT use zeolite in your aquarium
Many aquarium experts agree on the great contribution that this material has in a newly created aquarium. However, even in new aquariums, the addition of ammonia to the medium causes the zeolite to have to act as a short-term base. It's not a magic wand that resolves nitrates, phosphates or algae on its own.
On the other hand, once the ammonia levels have become stable, it is good to remove the zeolite. It is not recommended to use it as a permanent substrate. Instead, it is best to remove it and use conventional media. Conventional media include activated carbon or sand. In marine aquariums with sensitive invertebrates, continued unplanned use can stress corals if the reduction in nutrients is too abrupt.
Avoid it if your system does not have skimmer (in marine), if you do not perform frequent tests or if the aquarium is very small: it is a method aggressive which changes the ionic and biological balance rapidly. In planted aquariums with fish, prolonged use may reduce the amount of ammonium available for the cycle of nitrogen of the substrate/plants; use it only occasionally during peaks.
Finally, its use in conjunction with other nutrient reduction methods requires coherence: If you use carbon sources and bacteria, moderate the zeolite load and monitor KH, PO4 and animal behavior, as it may decrease KH y phosphate notably.
Choosing the zeolite and where to place it
Select the zeolite depending on the type of aquarium and objective:
- Sweet waterClinoptilolite in a mesh bag inside the filter. Medium sizes (2–5 mm) balance surface area/flow. Ideal for quarantines, overcrowding, or NH3/NH4+ surges.
- Marine: reactor designed mixes (e.g. ZEOvit) with controlled flow and agitation. The goal is to enhance the bacterial community to control NO3 and PO4.
- Fine mechanical lens: smaller particle sizes offer greater particle retention, but may clog sooner; use prefilter.
In canister filters, place it after the mechanical stage and before the biological stage if you use it as a chemical, or after the biological if you're just looking for a final polish. In backpacks or boxes, distribute the load evenly homogeneous so that the water passes over the entire surface.
Compatibilities, combinations and dosage guidelines
Common combinations and practical advice:
- Activated carbon: alternates with zeolite. Remove the zeolite when the ammonium is controlled and use carbon to toxins and color.
- Bacteria and carbon: In marine, zeolite-based methods incorporate bacterial strains and a bacterial food To keep the system stable, dose sparingly and observe.
- Skimmer: essential in marine to remove solids and bacterial biomass released after reactor agitation.
- Traces: zeolite can drag part of the trace elementsIn ultra-clean systems, it considers replenishing traces and vitamins based on consumption.
Guideline usage guides from recognized manufacturers indicate useful ranges: 250 ml per 200 liters in conventional chemical use, or 1 L per 400 L with a flow of 400 l/h per L in the reactor and replacement every 6–8 weeks. Always adjust to the biological load and the results of your tests.
Common mistakes and how to avoid them
- Put the entire load in at once: causes instability. Introduces 25–50% and scales within weeks.
- Without pre-filtering: shortens lifespan. Add pearl cotton and rinse the zeolite mesh before use.
- Do not measure: Monitor NH3/NH4+, NO2, NO3, PO4, KH, and redox if possible. Adjust based on data, not by eye.
- Lack of oxygenation: High bacterial activity consumes O2. It reinforces water movement and foamed.
- Compatibilities: avoid combining with other aggressive methods without planning (very powerful resins, carbon overdose).
FAQs
How long does zeolite last? Between 6–8 weeks in high-performance marine reactors and up to about 2–3 months in freshwater chemical applications, depending on loading and clogging. If you observe loss of effectiveness, replaces.
How do I rinse it? Rinse with aquarium or dechlorinated water before first use to remove fine dust. In reactors, the daily hustle and bustle serves as “self-cleaning”.
Is it suitable for phosphates? Indirectly, systems with zeolite and bacterial management can reduce PO4. If you are looking to lower PO4 quickly, use specific media (GFO) in a complementary manner.
In small aquariums? Its effort/risk ratio isn't worth it in nanometers if you're inexperienced. Better to have good water changes, biological filtration, and regular maintenance.
What granulometry should I choose? Medium (2–5 mm) as a starting point. Finer retains particles better but is fills up before; thicker offers greater flow with less specific surface area.
Advanced Notes for Reef Mariners
In systems oriented to short-polyp hard corals (SPS), zeolite helps to maintain ultra-low nutrient with more intense colors. In soft corals and LPS some specimens do not tolerate rapid drops in NO3/PO4: observe the fabrics and polyp and adjust load. If you see sudden negative reactions, reduced the amount of zeolite or the reactor flow.
During use, it may decrease the KH; monitor it and compensate for it with your supply system (kalkwasser, balling, or calcium reactor). Remember that in marine environments, the high ionic charge of the water displaces the ammonium from the zeolite, so its main role is biological and non-chemical. Without skimmer and without control of bacterial/carbonic dosages, the method loses effectiveness and can become unbalanced.
Sources and references
To expand and contrast the information, the following have been taken as a basis: technical documentation from manufacturers (e.g., Seachem Zeolite Fact Sheets and User Guides), reactor methodologies with zeolite mixtures (e.g. ZEOvit with 1 L per 400 L guidelines and recommended flow rate), and specifications of activated natural zeolite oriented to aquariums (exchange capacities, grain sizes, and fine particle retention). In addition, practical recommendations widely accepted by the marine and freshwater aquarist community have been incorporated.
These filters can be easily mounted inside a pressurized filter and allow for the control of aquarium coloration, in addition to what was mentioned with ammonia and biological filters. quite effective in those aquariums that are highly populated, since in these places maintenance tasks will be required due to the excess of waste molecules.
It is important to avoid the problems that it can generate due to its great capacity for molecular exchange. For it, We must install it little by little over several weeksIn this way, we will be getting the fish inside to adapt to the chemical changes in the environment.
It should be mentioned that due to bacterial activity, It is not advisable to keep the zeolite installed for more than three months. In general non-reactor applications, in high-performance marine reactors, replacement every 6–8 weeks is recommended to maintain system efficiency and stability.
Zeolite is a very valuable natural material that, when used judiciously, improves water clarity, controls ammonia in sweet and offers a base bacterial Robust in marine. To get the most out of it, always start gradually, place it after a good pre-filtering, shake it if you use a reactor and monitors parameters. This way, your aquarium will benefit from more stable and crystal-clear water without compromising its health. de peces and invertebrates.