Question
It currently takes about 12 hours for us to water our football field.  We have a Sta-Rite 3hp 25psi (58ft) pump on a Toro system.  The heads have orifices that have either the number 06 or 90, depending which way you look at it, on them.  We would like to cut our watering time in half.  Do we have the right size pump.  We need to replace it now and are not sure if we should get something different or not.  Should we change the orifices also?  If so, to what?

Answer
To shorten the time you water you need to put down more water then you are. The noz. (orifice) indicates the g.p.m.
Changing the noz. to a larger one will produce more water but you will need a larger pump. First you need to find out what that noz. is producing and then add up all the g.p.m. that there are running at once. Then find a pump that will produce those gallons with at least fifty to sixty pounds of pressure.