I am kinda confused on your setup. Here is what I did with my similar problem. I increased the lenght of the return line from 6 feet to 10 feet. And it worked great. You have gotten youself a ball valve and that should fix your problem.
Pump Problems
- Thread starter GooDyboy420
- Start date
Use a T piece with the ball valve, after the T so that any extra water just flows back into the sump.
I agree with Rallys and Oddball 
Why constrict your pump... That is not giving more filtration or flow it is taking away... And your pump will die sooner .... If I were adding ball valves ANYWHERE.. Myself It would be on the overflow... and that is only on a syphon system.. Wait thats a lie I would add one somewhere on my drains for easy draining in emergancy sits or for moving 
Add an overflow or shut one of the pumps down In my personal opinion
Why constrict your pump... That is not giving more filtration or flow it is taking away... And your pump will die sooner .... If I were adding ball valves ANYWHERE.. Myself It would be on the overflow... and that is only on a syphon system.. Wait thats a lie I would add one somewhere on my drains for easy draining in emergancy sits or for moving Add an overflow or shut one of the pumps down
In my personal opinion Bderick67;631472; said:
Personal opinion again.. this is even harder than adding a ball valve and you basically get the exact same effect on the pump
