Available in 1 Litre and 5 Litre bottles. Diatomix IV (eye-vee) is our full strength product with extra silica added. The extra silica is to ensure that there is enough in the water for ponds being topped up with rain water, water sources that only have low silica in them to begin with, and ponds that have high water recirculation. Diatomix IV can be used in garden ponds all the way to ponds larger than 10m2, dams, lagoons etc. Diatomix IV is also used in fish and prawn farms, drinking water storages and where the dose rate is higher.