Are under gravel filters obsolete?
Certainly not! Under gravel filtration will always be available for those hobbyists who want a good, low-cost biological filter for their freshwater or smaller, under-stocked marine aquariums. Wet/dry or “trickle filters” are a vast improvement in biological filtration compared to under gravel filters. However, most well-made wet/dry models are considerably more expensive than an under gravel system. Under gravel filters still play an important role for freshwater enthusiasts and marine aquarists on a tight budget. If you are setting up a serious marine aquarium, especially a reef tank, we strongly recommend the use of either the Berlin or Jaubert methods, or a wet/dry filter/protein skimmer combination, as opposed to an under gravel filter. However, if you are setting up a freshwater aquarium, or a very small marine aquarium (which we frown on), an under gravel filter still remains a viable alternative if budget is a concern, and in the case of marine tanks, if the tank is under-stock
