yeah, i knew i'd need a two head pump, or two pumps, but i know, you gotta be sure. would it not be possible to adjust it to run 24/7 at a very slow rate? the one i'm looking at adjusts in 0.3ml increments, so 24 hrs. that would be 7.2 ml per unit. i guess that's not precise enough is it? timers would complicate things. i was wondering why more people didn't go this route. maybe it's not as simple as it first appeared. thanks for yall's input, any more suggestions?