I've been using a couple of those cheap TOM AquaLifter AW 20 pumps on a timer to dose my 180g tank with macros/micros in seperate 1gal jugs. It works very well for keeping things very constant. This is not true EI dosing, where macros and micros are dosed on opposite days, but I am dosing half EI amounts every day both macros and micros.