Aquarium External Power Filters

External Aquarium Power Filters are one of the most efficient methods of aquarium filtration for the majority of Tropical & Coldwater aquaria. Because they are situated outside the aquarium (usually underneath or at the side of) they are very easy to maintain. The main benefits are that they have significantly larger filter media capacity over other types of filter & the flexibility to accommodate many different media materials. This type of filter also has a high turnover rate & as a general rule you should choose one that has a turnover of around 4 times the aquarium volume for Tropical & Coldwater & around 6 times for Marines or heavily stocked systems.