MarinePure: The Ultimate Biomedium

MarinePure: The Ultimate Biomedium

Tig Copepods Swimming

Managing dissolved waste products might easily be the most important—and oftentimes most challenging—task for a marine aquarist. Ammonia, nitrite and nitrate are the waste products that usually dwell at the forefront of the aquarist’s mind, as they should be. Ammonia and nitrite are, of course, extremely toxic and can wipe out an entire collection of animals within hours. Though it comparatively less harmful, nitrate can be even more tricky to manage over the long term. It can slowly build up over time, reaching levels that far exceed those in the natural reef environment. Being a key plant nutrient, nitrate can (especially if it is allowed to reach high concentrations) promote the rapid growth of undesirable forms of algae.

Most aquarists are at least somewhat familiar with the nitrogen cycle. In the aquarium, as in nature, nitrifying aerobic bacteria (e.g. Nitrosomonas and Nitrobacter spp.) convert dangerous ammonia and nitrite into less dangerous nitrate. Nitrate is converted into nitrogen gas by anaerobic bacteria (e.g. Pseudomonas spp.). Over the years, many different biomedia have been developed to provide a substrate upon which these beneficial microbes can thrive in captive systems. Many improvements upon that old mainstay, the undergravel filter, have sprung up along the way. This would include “bio-balls,” for example. These media are usually well-suited for nitrifying bacteria, as they are designed not only to provide a large amount of surface area to grow upon, but also provide the oxygen-rich environment that they require. Unfortunately, because they are highly aerated (particularly in so-called wet/dry applications), they exclude denitrifying bacteria, to which oxygen is deadly. Because of this dilemma, these types of filters have earned the dubious title “nitrate factories.”

If an artificial biomedia is to function more like a natural substrate (such as live rock), it should be capable of properly hosting both nitrifying and denitrifying bacteria as well as a rich community of microfauna. Such is possible if the material is extremely porous from its outer parts to its core. In this situation, nitrifying bacteria reside at the surface where they do their thing: make nitrate. Because the denitrifying bacteria reside nearby (just below nitrifiers in the deeper parts of the media), they have easy access to the nitrate and grab it as soon as it is produced. Miniscule critters (e.g. copepods) graze on the bacterial biofilm that develops over the outer surface of medium. To work in this manner, a substrate must meet three basic criteria:

  • It has ample habitable surface area for bacterial growth.
  • Its flow-through architecture allows for the moderate exchange of water (and oxygen) throughout its matrix, forming a strong oxygen gradient (lots on the outside, little in the inside).
  • Its larger pores (especially on the outer surface) provide a safe haven for tiny animals such as copepods and protozoa.

Bio-balls are sometimes very cleverly designed in a way to provide an impressive amount of surface area; in fact, some types might approach the amount of surface you might expect to see from a similarly-sized mass of live rock. But, the high surface area and high flow-through of bio-balls comes solely from their extremely irregular shape; indeed, they have a more-or-less smooth surface and minimal porosity. Thus, they are inadequate as a substrate if one hopes to cultivate a truly natural microhabitat as above described.

Sure, one cannot find a more natural biomedia than live rock. And live rock works pretty well for this purpose. However, our reef tanks are not exactly natural systems; they certainly do not behave like natural systems. For one, they tend to have a far greater ratio of fish to live rock volume than one would find on a wild reef. But, just like wild reef fish, captive fish must eat. And every time a fish eats, it produces nitrogenous waste. The usual result? An excess of dissolved nutrients and the typically accompanying plague of nuisance algae. Worse yet, water quality might deteriorate to the extent that livestock is lost.

Certainly, no one would ever suggest to not use live rock in a reef tank. Live rock has many ecological as well as aesthetic benefits. Indeed, a reef tank would not really be a reef tank without it. On the other hand, an aquarist can significantly improve the ecological functioning of their system (and greatly reduce their maintenance workload) by enhancing biofiltration. Perhaps the best way to accomplish this is with the addition of a premium biomedia. Of these, MarinePure is certainly among the finest.

MarinePure is a specially engineered medium that provides a mindboggling amount of surface area. Composed of an inert and extremely porous ceramic material, it provides an optimal environment for both nitrifying microbes and well as tiny creatures such as copepods. At around 150,000 ft2/cubic ft (510 m2/L) of surface area, one may create almost 20 times the habitable surface in the same amount of space compared to typical bio-balls! Its 80%+ open porosity promotes ideal water circulation with less clogging. Additionally, it provides a safe place for pods to live, hide, feed and reproduce. Larger-sized blocks (8″x8″x4″) have a deep enough core to support the growth of denitrifying bacteria and thus help to control nitrate.


MarinePure Biofilter Media PlateBecause it takes up so little volume relative to its total surface area, MarinePure can easily fit into the tight space of a sump, refugium, overflow box, trickle filter, HOB filter, etc. One might even use a larger block as a skimmer stand. MarinePure is completely safe, sustainable and eco-friendly. It is not harvested from the ocean and therefore will not introduce pests into your system. In fact, compared to live rock, it is easy to clean, sterilize and reuse. It is even available in a wide variety of shapes and sizes to suit your specific needs.

By enhancing certain natural processes, one can greatly increase the ecological efficiency of a captive system. MarinePure is a shining example of this. Appreciably reducing the threat of ammonia, nitrite and nitrate spikes while supporting high densities of algae-eating pods, this highly advanced material makes reefkeeping much easier at a surprising low cost!

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