Filtration FAQ page 2

What benefits will I obtain from using a canister or power filter on my aquarium?

Hanging power filters are an excellent way to help keep smaller freshwater aquariums clean. They keep the water polished and clear, and are very easy to maintain. We do not recommend hanging power filters for saltwater aquariums or large freshwater aquariums. We feel that the relatively small amount of filter material they hold offers little benefit to marine or large freshwater tanks. Canister filters are far superior but more expensive than their hanging power filter cousins. They last longer, hold a lot more filter material, use stronger pumps, and most operate with little or no noise production. They are ideal for most fresh or salt aquariums when mechanical and/or chemical filtration is desired. We do not recommend canister and power filters be used as the primary biological filter in any but very small aquariums. In our experience, they are inefficient for biological filtration purposes, as they do not offer enough surface area to cultivate a healthy nitrifying bacterial population, regardless of manufacturer's claims.
Canister filters are used to remove solid waste from the water column mechanically and also to hold chemical adsorption or ion-exchange material. Canister filters are also invaluable for pre-filtering water before it passes through an ultraviolet sterilizer to increase kill-ratio by clearing the water for better light penetration. Pumps combined with canister modules can also be used to pre-filter water before it passes through a chiller to keep the internal plumbing of the chiller clean, thus aiding cooling efficiency.
One of the problems with using carbon, phosphate-removal media or other chemical filtration media in the sump of a wet/dry filter is that water passes through the path of least resistance. A bag of carbon in the reservoir will only have so much water passing through it as the water would "much rather" move around it or over it. A canister filter allows the chemical media to be placed in a sealed chamber so that water must pass through the media where it can be treated.

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My aquarium store told me that if I install a wet/dry trickle filter system on my aquarium, I will be able to keep more fish . . . Are they right?

The answer is yes . . . and no! We don't mean to confuse you, but we feel that the ability to keep more fish in an aquarium may often be the wrong reason for using a wet/dry filter. Wet/dry filters (also sometimes called trickle filters) are a valuable biological filtration method. Too often, however, wet/dry filters are used as a means of over-crowding an aquarium, and this may eventually lead to problems. By connecting a pre-filtered wet/dry filtration system to your aquarium, you are adding additional surface area of the filter to the aquarium, thereby increasing dissolved oxygen levels in the water. The action of the water trickling through the media in the filter also helps raise oxygen levels in the water, in addition to providing an ideal environment for the cultivation of aerobic nitrifying bacteria. This can allow the aquarium owner to keep more fish . . . until the pump returning water to the aquarium fails, or the power goes out. Because the filter is connected to the aquarium by the action of the pump returning water to the tank, an over-crowded aquarium will quickly run out of oxygen if the pump (or electricity) should fail.
Wet/dry filters should be used because they provide a better environment for aquatic animals than an under gravel filter. They increase dissolved oxygen levels in the water. They encourage the growth of a good population of nitrifying bacteria. They do away with the need to keep an under gravel filter on the bottom of the tank, which can be useful for many living-reef or live-plant applications. They also allow the easy addition of a protein skimmer to the system. A good wet/dry filter system can often be expensive. If you are using an under gravel filter now, there is no doubt that you will see an improvement in the overall health of the aquarium by switching to a wet/dry filter. However, buying a wet/dry filter just to keep another fish or two or three may prove to be a disappointment to some aquarium hobbyists.

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I use carbon in my filters. How often should I change it?

Every two weeks to once a month. If the biological load is low (the tank is under-stocked), you may stretch this to once every two months. Some carbons or carbon/resin exchange mixtures may advertise that they last longer, and they probably do. Take what they recommend and cut that in half. It's carbon. It works by the process of physical adsorption. It gets clogged. If your filtration system depends on it . . . change it. We may take some heat for this, but one of the reasons we have a web site is so we can bask in the energy created when arguing and discussing the merits of one aquarium technique versus another. To those who would argue this, we say: "Get a microscope. Examine a grain of freshly-washed new carbon at 100X. You'll see hundreds of tiny pores in the structure. Then examine a grain of carbon that's been in your filter for a week. Unless your aquarium is immaculate, the holes will be filled. At that point, it doesn't work anymore." To those who advocate not using carbon at all, we say: "We can dig it! If it's working . . . don't fix it."

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For a wet/dry trickle filter, should part of the bio media (the trickle part) be completely submerged? If so, approximately what percentage of the media should be underwater?

In most wet-dry filters, part of the bio media is always submerged. That is where the term "Wet-dry" comes from. In a good wet-dry filter, no more than 1/3 to 1/2 of the media should be submerged.

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I have a 70 gallon fresh water tank with a hanging Supreme SuperKing filter. I'm looking to convert over to an Eheim 2215 canister (rated to 93 gallons). Would it be biologically beneficial to add a Bio-Wheel to this? Are these even compatible?

It would not hurt to add a Bio Wheel to the return of an Eheim filter. The hose size may be a problem, as Eheim uses a metric hose, but with a little ingenuity, you could probably make it work.

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I have an All-Glass 75E with a Magnum 350 canister filter and a Bio-Wheel 330. How often I should switch between the carbon canister and the pleated element in the canister and should I be adding extra carbon into the bio-wheel.

The micron cartridge for your Magnum should be saved for instances when your water is cloudy. It is also handy to run the micron cartridge while you do a water change to remove any dirt you stir up by accident into the water when you vacuum gravel. Other than those occasions, you should always run the carbon container, with a blue Bonded Sleeve around it. Change both carbon and sleeve every four weeks. There should be no need to add more carbon to the Bio Wheel Filter.

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My filter has a cartridge that is a pad with carbon inside. When I change the cartridge do I change all the carbon or just some of it?

Change all the carbon. Carbon in those cartridges gets used up quickly. The cartridges should be changed every two to three weeks.

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How does carbon rate against other filter media?

Carbon is an excellent chemical filter media for almost all aquarium applications. It is inexpensive compared to ion resin exchange media and is easily replaced. Unless you have a specific water chamistry problem or a toxic condition in the tank, carbon is probably the best all-around filter media for chemical filtration.

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I am upgrading a 10 gal tank to a 29 gal tank. I have four Goldfish. Would you recommend an under gravel filter for the new tank and can I also use a power filter with it?

I would use both filters and we applaud you for thinking of this in advance, as both types of filters serve completely different functions and many people make the mistake of only using one or the other.

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I have a protein skimmer and I plan on using live rock. Do I still need another filtration device?

Well, this depends on how many fish you plan to keep. If you will only be keeping live corals and invertebrates, and hardly any or only a couple of small fish, a protein skimmer may be perfectly adequate. However, that situation changes dramatically if fish will be the primary attraction in your tank. If this will be primarily a fish aquarium, you should definitely consider a wert-dry filter or at least a large canister filter.

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Frequent Aquarium Questions