For mine.. i have an eheim 1262 'main pump' and run it into the chiller..then the chiller output comes into my tank...Also i just plumb the entire set up with black tubing
I think option 2 makes the most sense. You won't need a separate pump and dumping it directly into the tank will preven already cooled water from being recycled through the chiller again.
mine is T eed off from the main pump. then the all the cool water that goes up to displayed is all mixed up with power heads and it cool down the tank fast.