Solutions may help you:
1. If the filter is blocking by dirt or stones, clean the filter or replace it with a new one.
2. If hose connection is cross-threaded, ensure the timer is installed properly and not cross-threaded.
3. If the inlet pressure is not sufficient to support watering needs, install a booster pump or other booster pressurizing equipment.
Note: This timer is built in with a solenoid valve. Technically, all solenoid valves decrease water pressure. RESTMO also has ball-valve timers that do not decrease water pressure. If you are not satisfied with the decreased water pressure, please contact us directly for more details about ball-valve timers.