You need to make it so if something gets lodged in your 1" bulkhead you don't burn up your pump or flood your house. You need to make it so one little object can't obstruct all your water flow.
Run a tube from the hole in the bottom of the tank to the top. Cut it to where you want your water level to be, and have the water flow into it that way.. Add a screen to it, and a pre-filter if you want to cut down noise..