Not as easily but it could be done. I would use a dosing pump, or some sort of drip. I think you'd get better control, and an easier system.
One thing I haven't seen mentioned. If you suspect you may need to dose, monitor your parameters more often and see how much they are dropping over what time period...probably the best way to know what is going on. To Davek's point, the monitoring and observation will, over time get you tuned in to being able to see what's happening in your tank.