id put a durso stand pipe on that sucker. i had to make one for my 180 because the idiots who made the tank left a 2 foot waterfall on the overflow and it was deafening. there are directions on this site on how to make one.
Exactly, you do not want to restrict the flow from the overflow thingy. The overflow thingy returns water at the same rate that the sump pump pumps to the tank. Restricting it could run your sump dry, burning up your pump and possibly overflow your tank.