Malta Aquarist Society

 What filter media are you using at the moment?

Internal filters usually have a sponge & a space where to add some charcole.

40% is alot of water & i would do 20% every 5/7 days & not a big one every 15 days.

Can you tell us how many litres per hour does your filter & how many liters is your aquarium?.

The filter media is sponge , I usually do water changes every 8 days corydoras.  I am not sure about the litres per hour but it surely is a 54ltrs tank

You can find the Litres per hour written somewhere on the filter or on it's box. Usually it is recommended, that as minimum the filter will turn the water 3 times the aquarium capacity.

Well I bought them as a package (aquarium, heater, filter, thermometer) from a local lfs so I presume the filter is ok . However I will check on the warranty of the filter , 99% I threw away it's box

So, if you bought them as a package, then i think that they're fine. Just make sure that you don't over feed & keep up the water changes.