Eheim 2203 miniFlat Shallow Water Filter Review

Filtration for small ripariums and paludariums.

Silvertip Tetra (Hasemania nana). Via Malene Thyssen/Wikipedia

The Eheim miniFlat shallow water filter, model number 2203, was tested for many months and performed flawlessly in a brackish water mudskipper habitat.  This miniature filter was used as a replacement for a very inferior filter I purchased from a large chain store.  Both filters cost me about $25 dollars but the historically reliable Eheim brand far exceeded the reliability of the off-brand filter.  The filter was used to power a spray bar within the mudskipper’s partially-filled, ten-gallon aquarium.  The spray bar helps to maintain high humidity which is necessary for the emergent growth of aquatic plants adorning the riparium.

Eheim miniflat filter
The Eheim miniflat filter is ideal for ripariums and paludariums that need shallow water filtration.

Eheim miniFlat Prep

  1. The filter includes a 6 foot (1.82 meters) power chord which was somewhat short for my use.  A 12 foot (3.65 meters) power chord would be more appropriate.  For example, a tall riparium resting on a 30 inch (76.2 cm) high stand results in the filter requiring an extension cord.
  2. It is always a good idea to rinse and test all new equipment before its use.  I submerged the filter in a tub of water and connected the plug to a GFCI protected electrical outlet for five minutes.  The filter was then disconnected from the electrical outlet and removed from the tub of water.  The tub was then inspected for debris or oil.  None was present indicating the filter’s pump functioned properly.
  3. The filter is designed to be placed directly on the bottom of a small aquatic habitat.  It is not intended to be used resting on substrate such as gravel.  It is equipped with suction cups which are to be secured to the glass bottom of a tank. Remove any algae or debris from the area where the filter is to be installed and gently press the filter into place.  The suction cups are tremendously effective and will tenaciously hold the filter in place.


  1. Eheim advertises that the filter’s pump circulates 300 L (79 gallons) of water per hour.  Much to my surprise, mine produced nearly 400L (105 gallons) per hour.   The water flow rate proved to be plentiful for the riparium’s spray bar.
  2. Eheim rates the miniFlat capable of pumping water vertically (called head height) to a height of ½ meter.  I found that rating to be completely accurate.  My miniFlat filter pumped water over ½ meter (20 inches) vertically.
  3. The pump is powerful but filtration is limited due to the small size of the sponge.  This should not be a surprise to anyone who has kept aquariums but a new hobbyist must carefully take this into consideration.  This issue is not a design flaw, rather, the filter is intended to be used in very small habitats having, for example, a gallon or two of water.  Larger habitats need additional filtration which I will discuss later.
  4. Service intervals, where the filter’s sponge needs to be cleaned, can be extended by simply placing a small, 7 x 3 cm (2 ¾ x 1 ¼ inch) section of bonded, blue filter padding over the filter’s intake.  (see photo).  The filter padding prevents large debris from entering the filter.  When filter flow diminishes, unplug the filter and remove and discard the blue filter padding.  Install a new piece of blue padding that is cut to the same dimensions and plug in the filter.  This should extend the requirement for complete filter cleaning to about once per month.
  5. The filter’s water flow adjustment is located on the outside of the water pump.  It couldn’t be in a more convenient location.  This is a huge advantage for making water flow adjustments after the filter has been installed.  Many other small filters have their water flow adjustments within the filter housing which requires removing and disassembling the filter to increase or decrease water flow.


  1. Cleaning the filter is very easy.  Unplug the unit.  Slightly pull in opposite directions to disassemble the pump housing from the filter case.  Wash the sponge insert in water taken from the aquarium or water that has been treated to eliminate chlorine.
  2. Cleaning the pump’s impeller is also easy.  The pump’s front cover slides off revealing direct access to the impeller.  Gently grasp the impeller with a pair of tweezers and pull it out of the cavity.  Wipe the impeller’s magnet with a paper towel and rinse the impeller in tepid water.  Use a Q-tip to clean the cavity and rinse it with tepid water.
  3. The most difficult part of filter cleaning is getting the filter’s strong suction cups to let go in order to remove the filter from the bottom of the aquarium.  The strong suction cups are fantastic and prevent rambunctious tank inhabitants from dislocating the filter.


This is a well-built filter suited for very small aquariums.  Those considering this internal filter should carefully assess the size of their tank and needs.  Additional filtration is necessary if the filter is used in a larger set-up such as my juvenile mudskipper habitat which is a ten-gallon, partially filled tank with 22.7L (6 gallons) of water.  I am a big proponent of sponge filters and find a single sponge filter used in conjunction with the Eheim miniFlat to be an outstanding combination. See photo.

Eheim is known for innovative and quality products and this one is no exception. Top that with a three-year warranty and the Eheim miniFlat clearly falls into the money well spent category.  Enjoy your fish!

Article Categories:
Fish · Lifestyle