| Heres a quote from the Aquasafe guys that should help you with the flow restrictor.
"The membrane makers would love to see us throw away 9 gallons for every 1 good gallon. No wonder, the membrane would last forever. The current generally accepted ratio is 3 or 4 to 1. Our new design can adjust the discharge for maximum water conservation.
It is simple. Unscrew the stem to the max and the restrictor is wide open in the "flush" position. Then very slowly tighten it until you get a drip....then a tiny bit more and then you will have a small flow. That probably is you point of maximum effectiveness in a low pressure situation. Time how long it takes to make a quart of good water. Then see how much waste water is generated. Play with it until the ratio is 3:1 and you are a "Green".
They are looking to make one quart of good water for every 3 quarts of waste water. | 
