I changed the filter about 1 1/2 weeks ago ant the tank is quiet dirty now.How often should i change the filter in my aquarium?How big is your tank, what kind of filter do you have, what kind of fish?
You should do a water change every 1-2 weeks, replace about 25-30% of the water
You do not need carbon in your filters, it really doesnt do much.
As far as sponges in filters goes you dont need to change it every time, but wash it out. Make sure you wash out the sponge with water from the tank. Put some water from the tank into a bucket and rinse out the sponge. If you use tap water it can and will kill the bacteria in the sponge. Yes in a fish tank bacteria is a good thing.
You filter may also have biomedia, which are like little rocks. Just like the sponge you rinse it out in tank water, not with tap water. Also you never need to replace biomediaHow often should i change the filter in my aquarium?every week :]How often should i change the filter in my aquarium?you should clean it weekly replace as needed don't have to many fish that will cause it to get dirty fast. remember 1 fish per inch of water from top to bottomHow often should i change the filter in my aquarium?Weekly..How often should i change the filter in my aquarium?it depends on how big your tank is, how long it's been running, the filter system and how much you feed...
Assuming you overstocked your tank by 5 fish, drastically over feed and have a 10 gallon tank running for a month...
weekly (at least)
assuming your tank is correctly stocked (~1inch of fish per gallon fully grown), running for a couple months, have a correct filter system and don't over feed.. monthly should be fine.
if your tank is dirty, possibly it may be algae growing on the tank sides.. scrub it off with a (NEW) tooth brush or something.
Also, you still need to clean your tank's substrate with a siphon tube and gravel vac. about once a month too.
