I see. Actually, the pump was too strong and the FT was almost overflowed, so I turned off power until the water went down, then started again. So the flow from FT to sump is too slow. I changed part of the pipe to 1 inch, most of the part is 1/2.
Because I'm afraid of re-do the hole in the FT, I didn't change the size of entire pipes. (I've had hard time to stop the leak from the hole in FT and GB.) I may need to re-do the hole first, I guess.