Set the controller up for 1 hour 3 times a day, once you have the controller setup get a timer at lowes or HD that can be setup at different times per day and make it run within the same hour you setup the controller on, make sure the time is setup for 15 sec only! This is what I use and it's the absolute safest way since you have 2 gadgets in-line protecting you. Generally timers are pretty reliable as long as the user programs it correctly so this is pretty safe, another thing you can do is slow down the dosing considerably so that you get the same amount in the tank in an hour than what you get now in 15 sec.