Originally Posted by DPfarr
The reservoir mist king tells you to use needs to be above the pump for gravity pressure to work. A reservoir of an RO unit is filled and then shuts off the incoming water.
This is true, but the reservoir only needs to be barely above the Mistking pump. I have a 5 gallon food grade bucket as my reservoir and it sits on the floor and the pump sits on the floor right next to it. I have no trouble getting the pump to work even when the reservoir water level is really low. So I don't think it's necessary to have even a foot of elevation for the Mistking to work, at least in my experience. No clue what the instructions say :-)
I had a big 55 gallon trash can that I used to use for my RO reservoir when I used to do a lot of planted tanks. I had it attached to a float valve and it worked just as you said. It was very satisfying to always come to get my water out of a full reservoir.