Tap water often contains heavy metals and sometimes chlorine which is harmful for fish and invertebrates. The water conditioner JBL Biotopol helps to bind heavy metals and to neutralise chlorine. For these effects the water conditioner needs about 15 minutes. Then the aquarium starter JBL Denitrol should be added to supply beneficial cleansing bacteria to the aquarium which are not initially present there. Only with the help of cleansing bacteria can fish excrements be broken down effectively. That’s why the fish stock can be added directly after the use of JBL Denitrol.