I am also using the TOM Aqua Lifter AW-20 vacuum pump as my auto doser. I've been using it for several months now with no problems. I have the pump sitting on top of my sump tank, using gallon milk jugs as my fert reservior which are sitting on the floor next to my sump tank. There is a short piece of tubing that goes from the pumps output thru the sump tank lid but well above the water level so there is no need for a check valve to prevent syphon. The ferts just drip into the tank. At 2min per day with the height I have my pump at it takes about 13 days for the reservoir empty. I put 14 days worth of ferts in and allow it to slighly overdose 13days and run dry the 14th, then refill. (1/13th of a dose overdosed isn't that much)I have this on one of my tanks. I too have it set up with a airline regulator. I set up the pump exactly where I wanted it. I then filled up the container with water and ran it for for a few minutes, I then timed it for 2 minutes with a container to catch the water. Measured this amount and set up my ferts to what came out in 2 minutes. I have it below my tank and it doesn't have a ton of head. Make sure that the bottle is below the tank though.