The frequency of filter cleaning depends on several factors, including the fish population, the amount of food distributed, and the type of filter media used. In general, cleaning every 2 to 3 months is recommended. It is important to monitor the filter flow and clean it when you notice a significant decrease. When cleaning, rinse the filter media with aquarium water to preserve beneficial bacteria. Avoid using tap water, as it contains chlorine that can kill these bacteria.

Since the EHEIM classic 250 is delivered without filter media, you have the freedom to choose the ones that best suit your needs. You can use a combination of mechanical (foam, wadding), biological (ceramic noodles, balls) and chemical (activated carbon, resins) filter media. Mechanical media is used to retain suspended particles, biological media promotes the colonization of bacteria that break down waste, and chemical media absorbs undesirable substances. Adapt the choice of filter media according to your water parameters and the specific needs of your aquarium.

Although the EHEIM classic 250 is designed for aquariums up to 250 liters, it is important to take into account other factors, such as the fish population and the type of aquarium (densely planted, reef, etc.). A very populated aquarium or with fish producing a lot of waste may require more filtration. In this case, it may be preferable to opt for a more powerful filter or add a second filter. Also make sure that the dimensions of the filter and its pipes are compatible with your aquarium and your furniture.