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Power Filter Impressions

By Steven Pro

Power filters have been a staple of aquarium keeping for quite a while now, and the various manufacturers are constantly updating and refining their designs to incorporate the latest trends and technologies.  Most every model, regardless of brand, is capable of both mechanical (trapping debris) and chemical (absorption of dissolved pollutants) filtration.  Some of the newer makes are attempting to also integrate biological filtration.  And, as you will see shortly, some have done this much better than others.

Aquarium Systems Millennium

With this model, Aquarium Systems strived to come up with a filter that combined mechanical, chemical, and biological filtration all in one unit.  This was probably in an attempt to compete with Marineland’s popular Emperor filter series.  Unfortunately, in my opinion, Aquarium Systems missed the mark with their offering.  The layout has the water first passing by the biological filtration media, then through the mechanical and chemical filter pad.  This forces debris to be trapped and collected in the biological media versus being caught in the disposable filter pad like it should.  This necessitates cleaning the biological media, which surely disturbs the colony of beneficial bacteria.  These units also have an interesting device that injects air into the biological media in an effort to aid in nitrification and oxygenation.  Regrettably, this makes the filter so noisy that I found it distracting enough to force me to disable the device.  On the plus side, they are easy to install and clean and seem to be reliable, but in my mind, these positives don’t make up for the deficiencies in the design.

 E. G. Danner/Supreme Aqua King

I included these filters for the old-school aquarists like me out there.  For the newer hobbyists unfamiliar with these products, this little walk down Memory Lane should serve to show you how far we have come and how lucky you are to have the equipment that is available now.

You can visualize these filters as a small aquarium that hung off the back of the main tank and had its own under-gravel filter.  Instead of placing gravel on top of the filter though, you were to put layers of Polyester filter fiber and activated carbon.  This worked ok, but these units had other problems.  The water got into the filter chamber by means of two large siphon tubes.  These were difficult to fill with water and a general maintenance headache.  The water was returned to the display by way of a powerful pump, but this pump was loud, ran hot, and was not designed to get wet.  Furthermore, it was balanced precariously over the open water in the filter area by two plastic bars.  This always was a delicate proposition with the possibility of a disconcerting shock hanging over your head.  It is probably best that these filters went the way of the dinosaurs and have been replaced by safer and more efficient designs.

 Hagen Aquaclear

These are some of my absolute favorite power filters.  They are simple, reliable, inexpensive, and have an extremely large and versatile media basket.  The standard foam block functions as a decent mechanical filter, and in time, will become colonized by beneficial bacteria and provide some amount of biological filtration.  They also use a large bag of activated carbon for chemical absorption and can be fitted with an additional product Hagen calls Amrid which is an ammonia removing clay.  This clay is sometimes also called Zeolite and is only for use in freshwater aquaria.

Their only potential problem is with their use in tanks housing messy fishes, like goldfish or large cichlids.  They have a tendency for the foam to become impacted with feces or uneaten food if not cleaned or replaced often enough.  This can lead to the entire media basket being lifted and causing water to spill out the back of the filter.  This can be remedied easily enough by making sure that regularly scheduled routine maintenance is carried out.  It is also a good idea to adjust the filter using the included leveling device so that the filter tilts towards the aquarium slightly.  This way, if the filter basket does get clogged, the water should spill over back into the aquarium and not onto the floor.  These units are my filters of choice for mixed community tanks when used with an undergravel as part of a larger filtration system.

 Marineland Emperor

These very popular filters employ mechanical, chemical, and biological filtration, and in my opinion they do all three well.  The water must pass through at least two filter pads that are designed to first remove debris and then, through the use of activated carbon, absorb dissolved impurities in the water.  All this occurs while a second impellor fan drives some of the filtered water up through a spray bar to get distributed over the biowheels for beneficial bacteria to work.  My only complaint is that these are one of the noisier filters on the market, although they are not as bad as the Aquarium Systems Millennium units.  Another potential problem with marine systems is with salt creep.  The spray bar, while making the biowheel operate more efficiently, encourages splashes and evaporation.  This leads to a good bit of salt on and around the cover of the filter.  Lastly, these units take longer than most brands to clear the air out of the U-tube, probably due to the large size of the suction tube.  However, these negatives are tolerable in light of the overall performance of these models.

 Marineland Penguin

These were Marineland’s first attempt at the trifecta of mechanical, chemical, and biological filtration.  As such, they were a good first shot, but they were not nearly as successful as their later Emperor series filters.  Their filter pad layout combines mechanical and chemical filtration, but is not as effective as the Emperor’s.  Also, their Biowheels are more prone to getting jammed with debris and subsequently stop rotating.

 Tetra Whisper

These filters are extremely quiet, easy to maintain, and reliable.  The early designs only performed mechanical and a modest amount of chemical filtration, but the later ones added a sponge for biological filtration.  This sponge was an improvement, although I would not feel comfortable relying on it for my sole biological filtration.  A strong positive for these filters is that the filter cartridges are so inexpensive that frequent replacement is easy to justify.  This is particularly useful when the aquarium being filtered houses messy fishes.  Another good attribute with this style of filter, especially when used in a tank of messy eaters, was it had a built-in overflow.  If the filter cartridges ever became clogged to the point that water would back up, the water would simply spill over the intake tube and fall harmlessly back into the aquarium.  Because of these features, this filter was my preferred choice when dirty fish were kept.  I am unsure of the current status for these filters.  I still see them available, although it appears Tetra is promoting their newer Tetra-Tec line (reviewed in the next paragraph) over this older design.  In my opinion, this is a real shame, as I don’t like the newer models nearly as well.


These are the ‘new & improved’ version of Tetra’s Whisper line, but they have some important differences.  They use a two-stage cartridge line up like the Marineland Emperor and Penguin filters, forcing the water to pass through two filter cartridges before returning back into the display.  This makes for very fine polishing of the water and a backup in case maintenance gets lax.  The downside is you need twice as many cartridges for the filter to run as designed, and the new cartridges are more expensive than the older models.  These units also come with two very unique features.  First, a heater component can be added to these units.  This allows for less clutter in the tank and protects the heater element from aggressive fish that could break it (large Cichlids are particularly prone to damaging these).  The other new attribute is a small surge device.  I would guess this is aimed at the marine aquarium market, but the surge is merely a few cups of water, not enough to make a significant impact.  I don’t feel that these are a major improvement over the previous generation filters.  If anything, the newer features are more gimmick than actual advancement.


Power filters can be real workhorses for many aquarists.  They can be especially useful for fish-only tanks, regardless of whether they are freshwater or marine.  A good one should be easy to install, effective, reliable, and easy to clean.  If it does all of this, it should make your life easier and help to keep your fish healthy.


WWM on Physical Filtration for Marine Systems

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