This is what I’m doing to make this do what I want. I purchased a Zurn 1-600XL Wilkins Water Pressure Reducing Valve from Amazon and put it inline between the expansion tank and my anti-syphon valve. This will keep the water pressure at 45 psi which will in turn maintain consistent flow. I can now calibrate the flow meter and use the resulting gpm to figure my nozzle output (GPM divided by number of heads in zone). This valve will also make the sprinkler heads more efficient by reducing mist caused by high pressure and will maintain more even coverage due to consistent throw.
