yeah, they run 24/7 but only for intervals. You can put it to "ON" but I think that is more for purging the line and the initial setup. The "run" setting has a set amount of times (150) it will dose, you set the amount you want to dose in a 24 hr. period. So if you set it for 5 liters a day it will divide that by the 150 times it doses. It would be too loud to run on the "Run" setting, that would drive you crazy. A cole-parmer pump would be better for that. What are you dosing?