Here is another link that you can read to see if it sounds familiar, and they are recommending 3/4 of a teaspoon to each gallon or 4 liters:
https://www.backyardchickens.com/threads/tetroxy-hca-280.1212797/
Does it say Tetroxy anywhere on the label or say that it has 280 grams? If so, the dosage would be 3/4 of a tsp per every gallon of water for 7 days. Does this label below look similar?
https://www.backyardchickens.com/content/type/61/id/7104679/