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About Using Canister Filters

Before You Buy A Canister Filter

By Stan & Debbie Hauter, About.com

Water Flow Rate Considerations
The flow rate on the manufacturer's instructions are reflected as an empty filter with zero head pressure (the canister is not having to pump water uphill). There are two basic factors that will effect or diminish the flow rate of a canister filter.

  1. Using extra media (carbon, etc.) or filter materials (poly filters or floss, micron pleat cartridges, sponges, etc.) inside the media chamber of the canister.
  2. Canister filters are often stored underneath an aquarium, so there is a lot of head pressure to deal with, and possibly a long distance of hose the water has to travel through. For the "hang-on-tank" type canister filter, you will get a water flow rate closer to what the manufacturer states, because there is little or no head pressure to contend with.
Taking the above two factors into consideration, the exact water flow rate can be determined after you buy a canister filter and have it up and running on your aquarium, or you can get an estimate by applying the flow rate equation in Step 7 of our How to Determine GPH Water Flow Rates, before you buy one. If after getting your estimate, taking the other factors into consideration, you are still not sure if your choice is a good one or not, it doesn't hurt to purchase a larger filter than you think you will need. You can never turn your tank water over too many times, but you can have a problem with not turning the water over enough, because this can result in poor water quality. A rate of 6-10 times per hour of tank water turn over time is recommended.

Other Feature Considerations
There are many brands of canister filters on the market to choose from. Some of the most popular traditional canisters are Ehiem, Fluval and Magnum, just to name a few (read reviews & compare prices). No matter what brand you buy, each manufacturer has their own distinctive characteristics in design, so doing your research on the different types is very important. Some are designed with special features, such as ones that use powder or diatomaceous earth to step the filtration up to very fine levels. Robert Fenner says these types can be sub-classified as "pressurized filters" that can really jack up your electric bill, so they are better used periodically rather than continually.

The best way to figure out what kind of canister filter you need is to determine what function you want it to accomplish, then decide from there which kind you should buy.

Another factor that can contribute to a canister filter not running at top efficiency and slow the water flow rate is ignoring proper or regular cleaning of the unit.

Next Page > Maintentance Tips
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Stan & Debbie Hauter
Guides since 1997

Stan & Debbie Hauter
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