Thanks for the advice so far guys, so then it's OK to connect a 1" pipe to my existing 3/4" AFTER the pressure tank? No isues with pressure dropping or anything like that? I did not do the "bucket test", but measured in PSI at the front spigot-came to 40psi when full open. Working through some of the Design Capacity charts(Hunter), I should be right around 8gpm and 30psi working pressure. So let me know if this sounds right: Cut into my existing 3/4" after pressure tank with 1" PVC and run it outside. Install Backflow preventer, then Valves. From here, do a reducing coupler back to 3/4" for the lateral pipes to sprinkler heads. Right? Question on backflow - can I use a PVB. Do I use both, or just one or the other?