2 55 gallon drums on a screw type motorcycle lift and an overflow tube. Lift one barrel up with an orifice built in to flow down into the grow bed. The overflow piped over to the second drum. When one drum is empty lower the lift, roll on the full barrel, raise it up and repeat. You could orifice the drums to increase or decrease the time. Ok everyone, go out and buy a motorcycle lift before they're all sold out. LOL.