I use Aqua5dry in the garden pond and aquarium. It is really very good effect against nitrite and nitrate. In the pond -no matter whether ornamental fish pond or swimming ponds, it is without hesitation and highly effective applications. The only slight drawback: it is not tolerated by Nixkraut in the aquarium. Does that mean that the Najas simply by use of dies or Aqua5dry care and ultimately scruffy; repeatedly observed! I do not know why, maybe to concentrated Baktis or certain enzymes that Najas not tolerate. Other plants and delicate shrimp or ornamental fish show no discomfort or even failures. Still, very effective! Whether koi pond, goldfish pond or natural pond without fish or with fish or swimming pond with or without small native fish species such as moderlieschen, bitterlings, minnows, etc.