NOTE: while I'm discussing this directly with Pete, anyone with any ideas/opinions outside of his, I'd still like to hear them!! So just have the bypass drop back into the tank then? You feel that'll alleviate some of the drama I'm dealing with? Just trying to understand what's happening in the pump here - is it that the diaphragms are having to fight resistance as they push the fluids through, or what? While this appeals to my pocketbook, I must confess that I'm fearful of putting my faith back into the D403... How strongly do you feel that this issue will be remedied via the replumbing? So just remove the existing unit and plumb the one in that you linked to? And once that's done, does that mean I'm gonna deal with massive clogs at my nozzle? Also, is it feasible to just purchase a different mesh for the existing filter? Thanks.