When should external filters be cleaned?
When should external filters be cleaned? The best clue is the filter flow, it is considered that when the flow drops below half as much as it was initially then the filters should be washed and cleaned. Another hint could be the length of time that it was not cleaned, and when we go beyond 6 months from the last cleaning we can think of going through the filters to see what’s in it. In this case it should be specified that time is not a rule, because if we still have good flow, few fish in the aquarium and clean water there is no need to maintain the filters. The third clue is the water quality, deposits on the substrate and plants, suspended particles in the water mass. When the water of the aquarium is loaded with dirt suspensions, when the substrate has surface deposits, when the plants show dirt on them, then it is necessary to think about cleaning the external or internal filters.
Now a fashion with pre-filters, some small filters, largely without the individual pump, is mounted before the filter input and retains much of the mess, leaving the main external filter to make only a biological filter. These pre-filters only make mechanical filtration and do not allow the thickness of the dirt to pass through the main filter. In this case, the pre-filter is washed more often, and the external filter is rarely used, sometimes the duration of operation of the main external filter without maintenance can exceed 2 years.
There are many myths about how to wash filter media in the filter, one of them is that it is only to be washed in aquarium water to not kill the bacteria and not to decimate the aquarium. I, in over 5 years of aquarium hobby, I washed everything that contains the filter external only under the direct jet of water from the network and I have never had problems. Put the filter in the tub, remove all the filter media, put a powerful jet of water on them and remove all the media. I am avoiding excessive cleaning, or the ladies are trying to boil the filtering media, because all that filthy filth, that shore and pieces of misery are billions of useful bacteria, biological bacteria that keep clean water and normal parameters. It should be specified here that clear visual water is not necessarily a good water for plants and fish, it must contain some good values of ammonia, nitrite and nitrate, and all of this is regulated by the biological bacteria in the filters. In larger aquariums, it is ideal to have two external filters that will only be cleaned once and for a period of one month between them. And still something to remember is that there is never a weekly change of water with cleaning the filters, but that’s another story to be said on another occasion so next time I tell you my motto “when something goes well in aquarium, do not change that well “