overflow box help

does the size of the overflow inlet have to be the same size as the pumps outlet or does the inlet have to be a bigger size

plz help me

 

Should be bigger, since it relies on gravity and not pumped.

 

You really need to determine the rating of the overflow box drain potential, I.E. : 300gph, if that's the size you purchased, and base what you are trying to accomplish with your turn over rate and your return pump GPH at the particular height from the pump to the outlet. For all purposes relating to drain vs return line size, everyone makes the drain diameter larger than the return, but you also need to keep in mind your pump rating vs your drain maximum potential.