for my 20g I mix into a gallon milk jug, 16 cups. Then I dose 1 cup a day. I suppose I could try dilluting it...but it would take too much thinking for my mathematically challenged brain.
For example, EI for a 20-40gal aquarium recommends 1/4 tsp KNO3 3x weekly. I add 4 teaspoons to a milk jug and add a cup of the mixture on MWF. This gives me 16 dosages, then I remix.