Does my 3/4 hp jet pump for a shallow well need a bladder tank?

We just installed a Utilitech 3/4hp Jet Pump for our shallow well of about 30 feet. We installed it with a Union just in case we had to remove it in the future and the Check Valve (Foot Valve) is above ground next to the well. It seems to be acting crazy! You have to turn it off at the main breaker every time we use it and the pressure gauge fluctuates really fast when building pressure or if you turn the valve off. I was hoping it would be easy just go out and turn a valve on and the well would work. We are just using it for irrigation with sprinklers but you have to prime it each time which takes about 20 minutes then you have to clean the algae out of the sprinkler for it to work? Would a bladder tank help this problem? Thanks for any input! :)