Mag-drive works too well!

Is it flex tubing or PVC?

 

what you may find is that if you restrict the pumps flow too much then it can create back pressure and wear out your pump faster, and also make it noisier, what i do is have a t-junction and have 1 part going back to the tank and the other going directly into the sump. with ball valves on each end of the t-junction you can tune it in so that the right amount of water is flowing into the display and then you can release the back pressure by opening and tuneing the other end back into the sump thuse using you pump to its potential and also reducing back pressure, noise and filtering your water more with extra going through the filter.