Reef doser amounts?

[o.c.d.]

I just pulled the Aqua Medic Reef doser twin RD2 out of the box and I'm trying to figure out how to set it I read the manual and it didn't break down the amounts of liquid dispensed . So in short of fiddlen for hours I thought I would try the easy rout If any one has figured the math on duration time = amount liquid dispensed please help me out. I'm trying to dose 20ml on each pump,still not sure if I should dose every 3,6 12 hrs for duration?If anyone has the info please and thank you ':confused:'