The flow rate of the X1 PRO-T can only be adjusted in manual mode, in Planning Mode the flow rate is fixed. If you want the machine to drip 20 ml in one hour, the machine will start working at the maximum flow rate of the pump at the beginning of one hour, and stop after the dripping is completed, until the next hour comes. You can only change the amount of dose and not the speed. For continuous dosing of Kalk I suggest the Kamoer FX-STP. Hope this helps.