RUGF: Reverse flow setups
There are certain caveats that should be noted. If you decide to use a UGF, reverse flow setups are better. A RUGF will keep nitrates lower by keeping the substrate cleaner and will aid water movement and circulation.
Proper Water Movement
The easiest way to achieve water movement is to have a power head in the tank for circulation. One must be careful though, a medium sized power head in a small tank will easily make a tornado- like environment and cause problems for small or slow moving creatures.
Wet/Dry Filter: best filtration systems for a fish-only tank
One of the best possible filtration systems for a fish-only marine tank is a wet/dry filter. Although commercial setups are fairly expensive, a wet/dry filter can be made very inexpensively at home with little effort. The ARCHIVE has a lot of information about constructing your own W/D filter system (as well as other fish related projects).
Many people advocate wet/dry filters for marine tanks stating they are the only acceptable solution. This is simply not true. Any one of the popular filtration systems may be used for a marine tank. The key to success is providing adequate biological filtration without trapping excess detritus. Trapping detritus produces nitrates and inevitably leads to problem algae outbreaks. Which ever filtration system you choose, be sure to rinse the mechanical filtration media at least once a week. Ideally you should rinse the media in old saltwater from the tank to minimize the disruption of any nitrifying bacteria growing on the media.
