you can get diff size of drip dosers anywhere from a half gallon to five gallon. the one that I have is a gallon. what I put in it is called kalkawasser. It is a powder that you mix one gallon at a time. I use one and a half teaspoons of kalk to a gallon. after you mix it you have to let it settle and pour only the clear water and try not to let the stuff that settled on the bottom into the drip. and then it has a tube that you put in your sump and it has an adjustment to regulate the drip. it is pretty inexpensive. Kalk is like 8 dollars for about 4 months worth. and the doser cannot be more thatn fity bucks. the one that I have is made by Kent