Your English is off but 4 liters would be close enough to agallon so 8 ml in a gallon which I about a tsp and a half. I would start at 5 ml per gallon or 1 tsp
a gallon is 3.8 liters, but like GrowGod said, whenever I run into this, I just multiply the amount per liter by 4, so it would be about 8 (7.6 to be more exact) ml/gallon according to the label. so yeah I would start at 4-5ml/gallon