Valve vs "cutting"

First, I'm going to be using waterfrommy salt water pool (3400ppm) NaCl and 5ppm chlorine. So things corrode away fast.

Anyway, I want to be able to pulse my jet.

Most of the cutters I've seen displace the flow and I'd need a place to capture the waste water - that I don't have.
The internal cutters look like they would corrode in a day.

Has anyone had success with an actuated valve on the input to the flow generator "cannon"?

Though the mass of water is high, it's velocity is low so the kinetic energy to stop/start might not be that bad?

I figure I'd definitely need an accumulator ne'er the valve to keep the water flowing in the pipe.

The problem with stopping flow through the main fountain body with a valve is that it introduces turbulence by causing pressure/momentum changes in the water. Getting a laminar flow requires as steady of a state as can be achieved in the fountain. The typical cutter design is used so that the outlet stream can be stopped without ever causing flow inside the fountain body to change. The other reason for a cutter is that very quickly cuts flow as close to the outlet of the stream as possible. Getting a clean head and tail on the stream cuts is critical to a really good looking display and the farther away you cut the stream the messier it will probably be.

You may be able to figure out a clever way to put an over sized valve in front of the outlet (over sized so the laminar stream doesn't touch the sides). I'm definitely interested in what you come up with! If I were to make a recommendation it would be to create a working nozzle first and then add a cutter later. As long as you leave attachment points it should be fine. Getting a working laminar stream first will give you a better idea of how to proceed for future steps.