Say what u want but i've had numerous tanks with herbies, no ato and no problem keeping them quiet. A valve will make all the difference because the fluctuation in the return compartment is now irrelevant because of the back pressure caused by the valve. A valve does nothing to change the speed of the pump.
I'm not sure where u got that from... It just gives it a consistent restriction to pump against... Anyways... I'm not here for a debate. I'm just offering suggestions for duncan.