I've read somewhere that 1GPM is about the highest it's "worth" tuning your loop to. Is this a reliable figure? Is it that cut and dry, or does it vary based on other factors? I ask because I'm about to install my first flow meter, and would like to set up my Aquaero to maintain a "good" number. Hoping that the D5 I'm using with two blocks and one rad can be allowed to spin relatively slow for silence.