I am a novice so please excuse my lack of knowledge but here goes ...

I am collecting rain water in a 275 gallon in order to water a small vegetable garden (only 100 sq ft of garden) with a drip irrigation system. So I need between 20 - 30 psi and not much volume (maybe max 100gph?). I want to control the system with a battery operated timer. Is there a self priming pump that I can mount in or on the tank that will turn on when a timer opens the valve.

Thanks.