PENAC W is a substrate additive. It prevents the substrate from becoming anaerobic and improves the substrate environment. It also can be added directly in case of shortage oxygen in the tank.
Sprinkle PENAC W evenly at the undermost layer of substrate.
Recommended dosage is 3 level spoons of PENAC W using the supplied spoon for a standard 60cm tank, 9 level spoons for 90cm tank and 12 level spoons for 120cm tank.
For improving the qualty of aquarium water, apply 1 level of PENAC W. It can be diffused evenly in the water by mixing it with some water in a container.