Part 1

It seems many people could use this information so here it is.

In order to determine what filter will work best for your needs, you first will need to know how they work and what the basic ideas behind each filter system are.

There are three different types of filtration that can be provided by a typical aquarium filter. They are mechanical filtration, biological filtration and chemical filtration.

Mechanical filtration: The removal of solid waste suspended in the water column.

Biological filtration: The use of nitrosomas and nitrobacter oxygen consuming bacteria to nullify toxic ammonium-based compounds to a safer substance - nitrates.

Chemical filtration: The use of chemicals to reduce or remove items from the water column. There are pros and cons to chemical filtration. Pros are it can remove odours, medication and certain waste by-products from the water. The cons are it also removes trace elements and other things fish need from the water. Active carbon also has a service life. This life could be anywhere from a few hours up to 7 days maximum. After the carbon is "used up" it can leach toxins back into the water system. Because there is no way to determine when the carbon is spent, it is not a good idea to leave it in a filter for more then a day or two. In general chemical filtration (active carbon) should only be used to remove medication and not as a full time filtration.

Flow rating: The maximum amount of water that can be passed through a filter at optimum operating efficiency. Expressed in gallons per hour (GPH).

Turn over rating: NOT the same as flow rate. The number of times the filtration system can run through the net water volume of a given aquarium. To find this number add the flow rating of all the filters in operation and divide it by estimated water volume of your aquarium. Example- 55 gal. tank with 2 Aquaclear 200's. After you add fish, gravel, and decor you have about 40 gal of actual water. Each Aquaclear moves 200 GPH for a total of 400 GPH. 400 divided by 40 equals 10. The filters turn over the tank 10 times every hour. Combining different types of filters is a good way to get what you need.

Hang on the back filters (HOB): These include Aquaclear, Whisper, and Emperor series.

• Pros: Easy to maintain, low cost, good general filter for a lightly stocked tank or pack them with floss and turn them into mechanical filters to support other filters in a system.
• Cons: Poor first pass efficiency, small filtering surface area, limited bio filtration.

Canister filters: These include Magnums and Eheims.

• Pros:Positive flow filtration (no bypass), the best first pass efficiency, larger surface area than HOBs.
• Cons: If overworked they can plug up and stop. As they filter, their flow rate decreases greatly (regular maintenance is important), expensive and harder to maintain then HOB.

Wet/dry filters A filter that uses a sump, overflow and return pumps to provide an all in one filtration system.

• Pros: Surface scum removed by overflow box, as water flows through the system it is fully oxygenated, they also act as degassing columns (carbon dioxide and nitrogen are expelled from the water), wet/dries house a massive amount of aerobic bacteria (best bio filter available), Unmatched flow and turn over rate can be achieved with these systems, can handle the heaviest bio loads, most act as mechanical and bio filters, sumps can be used to house heaters-this is allows for excellent heat dispersal and keeps the heater out of the way of larger fish.
• Cons: VERY costly, not recommended for planted tanks, if not set up and maintained correctly wet/dries can quickly become nitrate producers.

These are some of the more common filters used. I did not go into sand filters, bioreactors, protein skimmers, bio wheel operation or the old under gravel filter systems. But if there is a call for it I will discuss these and other in detail.

If you have more questions, please join the forum and ask your question there. We look forward to hearing from you.

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