Question
Hello and good morning. I just had an iriigation system installed and when each zone is running my pressure tanks gauge says 35 on some zones and 30 on othersand less when using water in the house. They the installers that is are suppose to come out today to fine tune my system and Im concerned im going to get ripped off. They are telling me they will be reducing the heads to a lower GPM AND IS THIS THE PROPER THGING TO DO AND WHAT IS THE PRESSURE TANKS GAUGE READING SHOULD BE SO i can make sure when they leave its setup properly. They originally told me that I had plenty of pressure when the salesman was making his sale now we are a little short though the heads in each zone are covering each other. What will actually happen when they reduce the gpm does this mean longer iriigation times I havr 11 zones

Answer
Reducing the GPM can and usually does result in less coverage by the sprinkler, unless they change out the entire sprinkler to one that is designed for that purpose.  I would be very careful about what they are telling you.  If the results are not acceptable, you may want to tell them that you want them to "split" the system by adding some of the heads on each zone to an additional valve.