do you think the efficiency could have something to do with how cold our water is? This company is promising 1:2 ratio on their cold water rated membranes;
http://reefbuilders.com/2011/04/07/g...old-membranes/
I just put my hand in a bucket of cold water from the tap for 5 seconds to adjust a heater and my hand started to get numb.
Most of us have good pressure - but Canadian water is frigid!