NT Labs M Green 7-2.5l-NT Labs Koi Care M Green 7 is a pond treatment for persistent fungus and external parasite infections. Treats fungus caused by Saprolengnia and protozoan parasites in pond fish. Recommended dosage: A course of treatment over 7 applications. Use when fish have white fluffy fungus growth on the mouth, body or are flashing against rocks etc. 10ml treats 700 litres 2.5 litres treats 7 x 25,000 litres Add one dose every week for 7 weeks. Switch off UV until 5 days after the final dose has been added.