OK, thanks wininja. Still it looks after a smaller problem. Even lighter one can act against it. Because the values all in the norm area are the only reasonable way is the density either is to be raised or much better to lower. I would lower the density upon 1,020. Takes every day some litres of the aquarium water and complements it with osmosis water. You make this as long as to the value is reached. I would recommend as a time frame for the lowering 2-3 days.Cyanos react very sensitively to a change of the density.
