Any way to do a one-time dose?

[lastlight]

I've got a program set for my 3 pumps but let's say I measure my params and realize I need to bring one back to target. For example my Mg is at 1350 and I need it at 1400. I adjust my dosing schedule upwards a touch but I need to also bring the tank back up to 1400. Anyway I can punch in 400mL of mg solution and tell it to do that over the course of the day? My program would stay intact and run but it adds this other one-time dose.