most simple plastic pressure reducers don't reduce static pressure; the water flow needs to be within the rated flow range of the reducer to work correctly. These type of reducers must be installed after a shutoff valve.

If you need to reduce static pressure you need to use a brass pressure reducer.

If your pressure is 100 psi for your irrigation system is to high. Are you taking your irrigation source straight from the mainline to your house which has street pressure? Is your house pressure 100 psi?

Yeah, I'm taking the irrigation straight from the mainline, using a stop and waste. I went to a local dealer and they set me up with a different pressure reducer. I'll post again with details and let you know if it worked.

You can put pressure reducers in series in order to step it down to what you require. Hope your house has a pressure reducer as well. Aloha