Aquarium Filter Media; types, capacities and more (This applies to ponds as well).

In this article I will discus three basic filter media types and subtypes of these.
These filter media types are Mechanical, Biological, and Chemical.
For more Aquarium filtration information, including canister filter media diagrams, please visit this article: AQUARIUM FILTRATION; how they work, advantages and disadvantages of each

MECHANICAL:

This media is primarily for trapping particulates in the water from large to small. In a canister filter or similar this should be the first phase of filtration (although many aquarists have done well with ceramic bio media used a coarse filter media that is both mechanical and biological provided it is rinsed in de-chlorinate tap water regularly.

Sub types include:
FINE FILTER MEDIA

*Basic aquarium floss or fiber which is a finer filter media.
In canister filters I will often use this to make a "sandwich", placing carbon or other chemical media in the middle for the final stage of filtration.







*Micron Cartridges for Filters such as Magnums or Aquarium Cleaning Machines. These cartridges can often filter down to diatom size and are excellent for cleanup, green aquariums, cloudy aquariums, even parasite infestations.





*Poly Filter Pads; similar to micron cartridges in their abilities (although usually not as efficient), but are excellent for canister filters.
As with filter floss, in canister filters I will often use this to make a "sandwich", placing carbon or other chemical media in the middle for the final stage of filtration.



*The Poly Bio Marine and similar pads by Boyds claim to remove heavy metals such as copper as well as phosphates, ammonia, and nitrites as well as certain organic via proprietary matrix of synthetic poly fibers.

My use of these has not quite stood up to the claims of this product as per phosphates, and ammonia/nitrites, however I have seen improvements in heavy metals and some organics. This said, most dense poly fiber pads have similar results as to organics and as per certain element removal, I would use with caution especially in planted aquariums. For those that use this product, I am not saying that it does not work, however the claims of what this product can do are just too broad and my test results to not mesh with claims and if all the claims were true you would deplete a tank too much of essential elements (that are important during times of stress such as new fish, shipping, etc.) and you would have no need for bio filtration (which of coarse is not true). I think the Wonder Shell actually stands up to its claims better (and even it is poorly named as nothing is a "Wonder" product.

My suggestion is to use a less expensive, non proprietary fine mesh Poly Filter Pad such as this one to the left, which is effective for trapping very fine particulates, free floating algae, and even some larger molecules; I use these myself and recommend them for the uses I just mentioned, I just do not recommend these for some of the claims of ammonia, phosphate removal, etc.

One more use of these types of pads (whether generic or name brand) is if used in an easy to change location such as a HOB or Wet/Dry filter they can be useful for lowering nitrates as well as long as they are rinsed every 1-3 days. How this works is this filter material will trap fine organic particles BEFORE going through the nitrogen cycle which would otherwise result in nitrates. The key is regular rinsing in CHLORINATED water so as to prevent the formation of nitrifying bacteria that would break down organics resulting in higher nitrates. This is similar to how the micron cartridges work (except on a much smaller and less efficient scale) in cleaning filters such as the Aquarium Cleaning Machines


MEDIUM FILTER MEDIA;
*Ehfi Synth by Eheim is an example of a medium mechanical filter media.

*Sponge and Foam Media; sponge and foam inserts/filters fall into both mechanical and biological categories. Their effectiveness can vary in both mechanical and bio abilities. The Hagen foam inserts pictured here is more coarse than some sponges (foam) and would be classified as medium mechanical media. They are not very dense and do not have as much bio capacity though.
The Hydro Sponge line (replacement sponges pictured, click picture to visit), has patented sponges of different porosity. The reticulated sponges found in the Filter Max #3, Hydro Pond and other is both dense (for good bio filtration) and medium in mechanical ability. The smaller model sponges (such as the Filter Max #2 and smaller, the Hydro Sponge #3 and smaller are actually a fine filter media (not as fine as poly pads and micron cartridges) comparable to filter fiber however with much more bio capacity. These do however require more rinsing do to their fine mechanical filtration.


*Cleaning pads as filter media; I have used the glass aquarium cleaning pads by Lees Aquarium Products for a medium filter pad they work great and are economical! I simply purchase the largest size I need and then cut to fit.




*You can also use a medium grade gravel or volcanic rock as a medium filter media for canister filters (see picture below for volcanic rock)

COARSE FILTER MEDIA;

*Ceramic Rings; As stated earlier ceramic bio media can be used for coarse filtration.







*Coarse gravel or better volcanic rock also makes an excellent coarse mechanical filter media (the volcanic rock is also a good bio media as well).






BIOLOGICAL:

This is filter media designed to allow the growth of nitrifying (and sometimes de-nitrifying) bacteria to remove nitrogenous wastes such as ammonia and nitrites. This is one of the primary goals of aquarium filtration!

Subtypes:

*Ceramic Bio Rings which go by many names are efficient bio filter media that have a capacity of 20,000 square foot per gallon. These however clog easily and need a monthly rinsing (in de-chlorinated water) to perform best. These have deep pores that can hold nitrifying and some de-nitrifying bacteria.
These are popular with canister filters, although ceramic bio rings can be used in HOB filters, and even wet/dry filters.
Due to the high volume of potential nitrifying bio bacteria in a small space, this is a desirable product when space is at a premium. However volcanic rock has similar properties and a rougher surface, so there are fewer tendencies to develop slime over the media and clog, which is the one negative of ceramic bio media.



*Bio Rings/Balls; these are popular in Wet/Dry systems where their high surface area (no pores) are exposed to oxygen rich air. Bio Balls can also be used in HOB and built in Wet/Dry filters effectively, although they will often be exposed to less oxygen in these systems. Bio Balls generally have from 100 to 160 square feet per gallon and are generally much more economical than ceramic rings when large quantities are needed, such as wet/dry filters.
However, bio balls are purely for aerobic nitrifying bacteria as there are no deep pores for the formation of de-nitrifying (nitrate removing) bacteria. This makes bio balls a poor choice for marine aquariums despite the popularity of bio balls in many marine systems over the years (although thankfully many have realized the “nitrate factory” potential of bio balls and saltwater use is rare nowadays).


*Bio-Chem stars are made from a porous polymer in a process that forms a very fine 50-70 micron internal pore network. Bacteria grow within the star, colonizing the entire structure. One Bio-Chem star has 33 times more bacteria growing area than the average bio ball. The stars can be used to float on the water surface in external power filters.


*Cured Live Rock Crumbles; this has been VERY effective for me in canister and wet/dry systems (in place of bio balls or ceramic bio media), rock piles, Refugiums, mud filters and other marine systems for both aerobic (nitrifying) and anaerobic (de-nitrifying) bacterial functions. Generally I use live rock pieces about 3-4 cm in diameters.

*Volcanic rock; I already mentioned this above for mechanical filtration however I will mention it again as it is very porous and makes an excellent bio media for aerobic and anaerobic bacteria for both fresh and saltwater. I have generally used smaller pieces (based on availability) of volcanic rock as compared to live rock crumbles; 1-3 cm.
Volcanic rock is excellent in pond filters and marine aquarium systems!


Bio Home is a new products that has a lot of promise, especially in marine aquariums due to the availability of deep pores away from oxygen where nitrate removing de-nitrifying bacteria can form. Bio Home is made from sintered glass making it much more porous than the other traditional filter media available.







*Sponge and Foam Media; Sometimes incorrectly thought of only as a mechanical filter media (or the opposite), however sponge filter media which can vary in capacity per square foot depending upon the type and brand is one of the better bio medias especially when price and space are considered. I have use sponge filter media such as the Hydro Pond #4 for pre filters on pumps in sumps for refugiums or similar filters with very good results.
The sponge is also how several HOB filters utilize nitrifying bacteria such as the Aqua Clear or Whisper (with the sponge insert). In fact I did several experiments several years back comparing sponge filters and sponge equipped HOB filters to the much hyped bio wheel and the sponge media one the tests (which at the time caught me by surprise as I was a believer in the bio wheel hype, not that the bio wheel does not work)! Please see this article about bio wheels: “Do Bio Wheels really Work”.
The bottom line is most high grade sponge filter media such as that used by Hydro Sponge and Aqua Clear are almost as efficient a bio media as many other types such as bio rings and better than bio balls and sponge media has the advantage of ease of rinsing which is a plus over some other bio media.
Please read this article for more information about sponge filtration: “Sponge Filtration, how sponge filters work”

CHEMICAL (Absorbing):

These are filter media that absorb or bind chemicals and toxins within the media.

Sub Types:

*Carbon; a very popular chemical filter media that is often over used in established aquariums and sometimes ponds as well. A healthy established aquarium (fresh or salt) with regular water changes generally needs little carbon. In newer aquariums I will often use about 1-3 teaspoons per 10 gallons. Carbon will NOT remove or absorb ammonia, nitrites, or nitrates. Carbon is very useful in removing medications after treatment or even between doses.
There is controversy in what essential minerals carbon will absorb or what activated carbon will or will not absorb in general. I will state based on my own experience and scientific evidence that carbon has many uses in aquariums/ponds but is also over used or incorrectly recommended. Although I use little carbon in my established healthy aquariums and ponds, I disagree with those that state it should not or rarely be used (based on some false assumptions of what carbon removes or adds to water). On the flip side I also disagree with those that make carbon the answer for water quality issues such as nitrates for which carbon does not remove.
Activated Carbon is very useful for removing most medications after or between treatments (this is where I strongly recommend its use), although even here, carbon does not remove most copper formulations effectively.

Here is an incomplete list of what carbon does and does not remove based on a University Research Paper;
What Carbon CAN remove:
Inorganic Contaminants:
Organic Arsenic Complexes
Organic Chromium Complexes
Mercury (Hg+2) Inorganic
Organic Mercury Complexes

Organic Contaminants:
Benzene
Endrin
Lindane
Methoxychlor
1,2-dichloroethane
1,1-dichloroethylene
1,1,1-trichloroethane
Total Trihalomethanes (TTHMs)
Toxaphene
Trichloroethylene
2,4-D
2,4,5-TP (Silvex)
Para-dichlorobenzene

What Carbon CANNOT remove:
Microbes,
Sodium,
Nitrates, nitrites, ammonia
Fluoride,
Hardness.
Lead and other heavy metals are removed only by a very specific type of AC filter

Please reference this study for more about carbon:
http://www.ag.ndsu.edu/pubs/h2oqual/watsys/ae1029w.htm


*Boyd’s Chemi-Pure; this is a popular product that I must be missing something about as I have used it several times in my maintenance business and have never quite seen this product meets its claims. In fact in marine aquariums I have seen very unstable pH when this product is used. I also have some problems with the claim of “NO CLEANING - Necessary for health of fish”, I personally feel very strongly about regular water changes even with products I recommend. This all said, I do know persons in this hobby whom I respect who like this product, so I will leave it at that.

*Bio-Chem Zorb; this product by API provides a home for colonies of nitrifying bacteria in both fresh and saltwater aquariums. Space-age porous polymer allows for rapid transfer of oxygen and water. Bio-Chem Zorb is made from a research grade carbon/resin in a flow-through nylon pouch. Removes aquarium pollutants, improves oxygenation, and will not remove trace elements from saltwater.
I have used this product (which is very similar to Boyd’s Chemi-Pure) with moderate success however I find its cost vs. results generally a poor value.



*AmmoChips (AmmoCarb, Zeolite); this is only safe for use in freshwater aquariums as salt will leech out the ammonia it absorbs. This is a useful product (especially when combined with carbon in freshwater aquariums) for new aquariums, overcrowded aquariums, or when used in conjunction with carbon after medication treatment that may kill off some nitrifying bacteria such as Erythromycin.
I generally use this product over straight carbon when I even use carbon in freshwater (the keyword is even use as I do not often use carbon in healthy freshwater aquariums).



*Wonder Shells; a poorly named product that even though it’s name implies more than it delivers is an excellent product (more so than Chemo Pure in my experience). This product can be placed in your filter like other media although it is generally place on the bottom of the aquarium. What this product does is it adds several trace elements (electrolytes) a calcium as it dissolves according to natural water chemistry. The results have excellent in many aquariums, especially livebearers, goldfish, betta, African cichlids, and Discus (and many more).

*Resins; there are many resins (not all are safe for both freshwater and saltwater) from phosphate removing resins to nitrate sponges. My results are generally good with the main issue being expense as most of these resins are very expensive to use in the quantity needed for say nitrate removal. Hagen Green-X (Phos-X) is a product that I have used successfully in marine and freshwater aquariums. Green-X removes phosphate, nitrate and nitrite and it relatively inexpensive when compared to similar products. Unfortunately I believe that Hagen has discontinued this product.
Another popular resin is Purigen. Purigen is a premium synthetic adsorbent made up of unique macro-porous synthetic polymer that removes soluble and insoluble impurities from water at a rate and capacity that exceeds all others by over 500%. It is not a mixture of ion exchangers or adsorbents. Purigen controls ammonia, nitrites and nitrates by removing nitrogenous organic waste that would otherwise release these harmful compounds. Purigen’s impact on trace elements is minimal. It significantly raises redox.


*Water Softening Products; Peat or Peat Pellets are popular for maintaining a lower pH in Amazon River or similar aquariums. I prefer the newer Bio Lif which is made from almond leaves which naturally lower pH as well as aid in the control of some pathogenic anaerobic bacteria. All these products tend to yellow the water, so keep this in mind, however this a very natural color for lower pH waters.