They will help, but I am sure you will see your corals not being so happy without the extra water flow.
Plus the more water flow you have the more oxygen the tank has, if you have a fairly decent populated tank with corals and fish theose oxygen levels are going to be reduced. You will see that with the actions of the fish by labered breathing, less motion. The corals wont open up or extend there polyps as much.
I am sure that extra flow helped out with the removal of detritus, and without that flow you can get a decnt amount of dead spots and detritus build up.