Doser Help Needed (set-up)

[Arok3000]

Originally Posted by Snaz

I don't have a doser so I may be wrong. For a doser to be accurate the hoses must always be completely full otherwise the pump well count it's cycles and nothing is deposited until the tubes fill up again resulting in an under-dose. The check valves ensure the tubes are always full to the brim.

This.
If you have a vertical run into your tank, then after the dose, the lines may allow air to creep up the tube, depositing more solution than anticipated, and not as much solution the next time the pump runs.

The pumps themselves will prevent backflow from the tank into the product containers in the event of a submersed line.
That being said, I just stuck mine after my containers so that air doesn't creep in on the input side, since my outputs are a horizontal span with a 1" vertical drop into the tank. My setup really doesn't really need the check valves, but I figured I'd use them anyways.