Flow-Controller and filter are color-coded in regard to Gallons Per Hour (GPH) @ a standard of 20-50 PSI which is recommended for optimal performance. No pressure regulators are required for PSI under 50. It is recommended that you use only Top-Hat style jets with Maxijet Pop-Up Spray Adapters® because when retracted into the base they remain flush with the top to keep out debris and sand.
For water pressure over 50 PSI, use a 50 PSI pressure regulator.