Kusuri Formalin 30% is best used with Kusuri Malachite Green for the effective treatment of most single cell parasites including White Spot, Costia, Chilodonella, Oodinium and Protozoan Parasites. Use above 12.5°C (54.5°F) Kusuri do not recommend the use of Formalin with any salt solution. Please ensure that you read, understand and follow all Health and Safety guidelines on the bottle. Please do not eat, drink or smoke whilst handling chemicals. Wear disposable vinyl or latex gloves and appropriate eye protection. 250ml treats 15,116 litres (3,325 gallons) of pond water 500ml treats 30,232 litres (6,650 gallons) of pond water 1 litre treats 60,463 litres (13,300 gallons) of pond water


Size: *
  • 250ml
  • 500ml
  • 1ltr

Learn More

Use 75ml per 1000 gallons (4546 ltr) of pond water. Treat up to 3 times, 7 days apart. 

DO NOT OVERDOSE. Over dosing can cause fish fatalities.

For use above 12.5°C (54.5°F)

Switch off UV steriliser until course of treatment is complete. Tighten cap and mix well. Measure out the correct dose. Fill a clean watering can with fill with pond water, then add Formalin. Gradually sprinkle across the surface area of the pond over a 1- hour period. Do not use below 12.5°C. Never use Formalin with salt, or if the liquid has gone cloudy, or has crystallised.

Stop feeding during the course of treatment because Formalin will reduce the bacteria in the filter, continuing to feed will cause an ammonia spike.