HOB filters are the most common aquarium filter type. Top brands: AquaClear (Fluval) - the hobbyist favorite for customizable media chambers. Seachem Tidal - clearest visibility, easy maintenance, magnetic surface skimmer. Marineland Penguin - cheapest with biowheel. Sizing: rated 4-6x tank volume per hour. AquaClear 50 = 200 GPH = 40-50 gallon tank. Always oversize one tier. Media options: coarse + fine sponges (mechanical), bio-rings or BioMax (biological), activated carbon or Purigen (chemical). Customize the chamber. Pros: $25-80, easy maintenance, visible water level, surface agitation, customizable, no setup complexity. Cons: visible from outside, evaporation noise, limited capacity vs canister, doesn't suit reef tanks. Maintenance: rinse mechanical media in old tank water every 2-3 weeks; replace carbon every 3-4 weeks; never replace bio-media all at once.
Reviewed by the Fast Aquatics husbandry team · Updated May 2026
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