Hi Lawn,

In my opinion, oh by the way you have done a great job with providing enough information, thanks, you have one thing to check and two options. Others may have a different opinion or actually better advice. First make sure you are getting your 4 gpm by capping off 2 of the sprinklers and connecting a threaded nipple to the third with a 90 degrees bend set up. Measure the flow from that outlet set up and see if you are receiving what you think you should be getting. If you aren't your valve may not be opening all the way. If you are then replace your nozzles with lower flow ones say .75 gpm. A smaller orifice with throw water farther and you only need to water longer to get your needed water. Option two which is where money and effort come to play is to increase the number of zone to 4 and decrease the head flow slightly to 1.5 gpm/head. With the pressure you have you might try rotory heads which have more flexibility in nozzle size and throw. Any way you understand the trade offs now. Is there any way to increase your flow with another tied in source?
Good luck and aloha.

Thanks Lehua for the quick and informative response! I have checked for flow at the sprinkler and unfortunately 4 gpm is all I can get. I have only a 1/2" copper pipe available and there is the flow dilemma. Where is a good place to get 2" pop-up .75 gpm nozzles and will they throw the water far enough to cover a 20' spread (10' radius)? Can I replace the nozzles in my existing Toro sprinklers? If not no big deal I just need what pop-ups to buy. If I could get 360 degree pop ups that would cover everything that would be awesome. I could also try rotary but I am afraid with a rectangle shape they might water the redwood fence too much? Sorry for all the questions but as the name suggests I am a noob at this! Thanks for your help!

New Toro Product:
RIVERSIDE, Calif. (Nov. 2, 2008) - The new Toro Precision Series Spray Nozzles with Toro-exclusive H20
Technology represent the most significant breakthrough in spray nozzle technology in over 60 years. These
nozzles deliver a significantly lower precipitation rate, expand the selection of arc choices for increased
precision, and conserve water with better edge definition and improved wind resistance while effectively
maintaining turf and landscape.

That product may be what you are looking for. Check the link out below.

Here is a link that might be useful: Toro Precision Spray Nozzle

Hi lawn,

I looked at the site and the technical brochures. The throw will be 15 ft at 50 psi pressure. This the max distance. The flow will be variable probable with probably a manual screw adjustment in the center of the nozzle. The flow range is 0.038 to 2.4 gpm. That should do it for you. Talk to your supply store to get more detailed info. This is the lower flow greater throw distance theory. You will have to run your zone to get the same amount of water coverage you need. Give it a try.

ri-ohio has very detailed irrigation knowledge and field experience. I am glad he is participating in these threads. Aloha.

Thanks very much ri ohio and Lehua! I will give that a try. If there still is not enough flow I will cut back the number of heads and use a rotor in each zone. Thanks again!