From what i have seen, the pumps don't actually run at those pressures. They are advertising "dead head" pressure. I have tested a few of the 200psi pumps from different vendors, they all ran within 10psi of the Aquamist pump once you started flowing. At very small jet sizes they do hit about 200psi, but go there nearly immediately after the pump turns on because for a pump that will put out 3700cc a minute free flow, 200cc of flow is dead head with a slight leak.

I have sat in Aquatec's engineering offices for lengthy discussions and to me they categorically said that the pumps cannot run at these pressures. Maybe a dead head spike, but not run.....It's advertising gimmicks. I haven't seen everything, but have yet to see a 250psi line pressure with a M10 or larger jet.

And trying to make them run at higher pressures actually makes they worse for the application. The spec they use makes them run slower(more pulsing) and draw double the amps of the Aquamist spec pump.