Well if you know how much you want to dose here is what you do. Divide the total daily ml dose into how many hours you want the dosing pumps to run. Next divide that number by 1.1(that's how much the pumps dose a minute. I dose alk at the top of the hour and ca at the half hour. Program runs for 12 hours while my lights are off.
My programs:
Alk
Fallback off
OSC 000:00/003:30/056:30 Then On
If time 12:00 to 23:59 Then Off
If pH > 8.4 Then Off
Ca
Fallback Off
OSC 030:00/003:30/026:30 Then On
If time 12:00 to 23:59 Then Off
If pH > 8.4 Then Off