Frequently asked questions

Freshwater Care

Nitrite level remains very high for months

Hello, something is wrong with the filter if the nitrite level is still that high! The biological performance of internal and external filters is the same, provided the filters are...

Freshwater Care

Nitrite levels remains at 0.3 mg/l (ppm) for a longer time

Hello, the nitrite peak may indeed occur or be present later than after 4 weeks. Using a really highly active filter medium (sera siporax Professional) and a biostarter (sera bio...

Freshwater Care

Peat (sera super peat) against algae?

Hello, peat is indeed active against algae, even in two different ways:many algae grow better in alkaline water containing carbonate than in acidic water low in carbonates - and...

Freshwater Care

pH value remains below 6.5 even after a water change

Hello, Concerning "R/O water":just a remark: the pH value of R/O water is not really important - it can vary strongly as it is not buffered. Furthermore, conventional pH electrodes...

Freshwater Care

Plants do not grow but dissolve

Hello, it is very likely that plant pathogens or the like can be excluded - but there are many possible causes:  High conductivity (above approx. 500 µS/cm) Due to the very high...

Freshwater Care

Quick or slow water flow in the filter?

Hello, in fact, a cross of the two would be optimal. In case of high nitrate pollution, this can be achieved by a combination of a conventional "biofilter" (typically with flow...

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