This might help.
Quick Medication Dosing Tip - Since most medication dosing directions are meant for larger tanks and some medications come in tablet or capsule form, it can be difficult to dose a small container. There is a trick to doing this.
If your medication calls for one capsule to 10 gallons, grab a small container that can hold water. using a measuring spoon, measure out 10 teaspoons or tablespoons full of water into the container (it doesn't matter which you use as long as you use the same unit of measurement the whole way through). Dump the capsule or crush the tablet into the measured water. Then dispense the medicated water into your isolation container - if it is a 1 gallon container, one teaspoon/tablespoon will be the correct medication dosage. This method works for any size treatment container, just be aware that most medications lose effectiveness after 24 hours in water so you will have to discard any unused medication using this method.