More and more manufacturers are using filter media that can be re-used.
One of the most common is foam, which often is used to trap suspended debris. Although it can be re-used, it needs to be rinsed every couple of weeks to maintain a good dirt magnet.
Foam is also used a biological media as well, although more and more porous ceramic rings and blocks are also being used. Both of these need to be rinsed clear with safe water.
Standard tap water is deadly to bacteria, so it is much better
to use the water removed from the aquarium before you discard it.
Rinsing the foam and other biological in the bucket will remove most of the dirt, but the water is already dirty.
I tend to treat a gallon or so of tap water and use that for the rinsing. It is a bit more expensive than using old aquarium water, but the results offer cleaner media.
There are three types of *filter media*:
Each requires different schedules of maintenance. A standard maintenance routine every two weeks will most often fit into the media longevity.
Carbon, for instance loses its activity after a month at maximum, so replacement every other maintenance period is simple.
Rechargeable resins require varying periods between recharging. One, Zeolite, or ammonia remover can be recharged, but I rarely do it. It is cheap enough and so difficult to when it is still active that straight replacement on a monthly basis is probably the safest way to deal with it.
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Beginning Aquarium Tips