Filter performance goes down very quickly, water becomes cloudy


We have had a 200 liter freshwater aquarium for 1.5 years. Unfortunately, the water has recently become very cloudy. In spite of gravel cleaning and regular filter cleansing, the water becomes cloudy again after a few days, and the water only drips from the filter outlet hose.

at least the biologically active main filter media should be cleansed as rarely as possible. The minimum time before the biologically active filter compartment needs to be cleaned due to clogging is 6 - 12 months. Otherwise the bio filter is insufficiently sized or overburdened - which in fact means the same. Quickly deteriorating water flow along with cloudiness indicates the following situation: Due to the present nutrient supply the bacteria multiply so rapidly that the settling space provided by the filter is not sufficient, thus causing the filter to become clogged, while bacteria multiply also in the open water due to lacking settling substrate.

The prefilter media as well as the hoses may be cleansed or replaced more frequently if necessary.

Considering the water flow direction, the filter should be equipped as follows:

1) Prefilter (1/4 - 1/3 of the available space): Clay tubes (sera biopur), green filter fibers (sera biofibres) or sponge. The material sholuld have rather coarse pores as to prevent unnecessarily quick clogging, and mechanically stable as to prevent it from collapsing.

2) Main filter (2/3 - 3/4 of the available space): highly active biofilter material (ideal: sera siporax)

3) Filter mat or a thin layer of filter wool for removing fine particles (make sure the fibers cannot be caught in the motor!)

The filter media mentioned in 1) and 2) may be separated with a filter mat as to prevent them mixing.

If required, special media such as sera super carbon (active carbon), sera phosvec Granulat or sera super peat (blackpeat granulate) can be placed after the main filter material. The last mentioned media, however, is in fact not a filter material but a water conditioner applied in the filter.

Best regards

sera GmbH

Dr. Bodo Schnell


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