I dont know if this works or not but i was reading that if you put the maxi jet mod propeller on the K4 that it will double the flow! that would bump it up to 2400 gph.. i may just try this, does anyone know where to get the maxi jet mod from?
just looked at that thread and tough ive never heard of anyone trying it, id say its worth a shot! ill let u be the test dummy though let me kno if it works