help with sump pump

[joy13]

This is the pump I had http://anythingsaltwater.com/4100-pump-p-1487.html and it was very noisy so I got this one Amazon.com: Tunze Recirculation Pump/Powerhead Silence 1073.040: Kitchen & Dining Since the old one was dialed down at the lowest flow I thought I could be by with the tunze. The tunze is emptying my sump in less than a minute, I have it at the lowest flow possible. Would it be alright to use the ball valve long term to keep the flow down or would it cause the pump to over heat?