Bouncing Pressure gauge.

[BravoTwoZero]

That's right, so it will be almost completely closed. (Just a side note, having air in the line would actually help dampen the oscillations as air is compressible vs. water which is not [for all intents and purposes here], much like how air gaps are used to dampen water hammer in household plumbing.)

Reefer, Thanks for the info re needle valve. I tried with a flow restricter inner (no idea what rating it is) but it cut down the bounce from 3-9 to 4-6. So if I can close it down a bit more I my get a steady needle.

 

[BravoTwoZero]

Great news I have got the gauge to work. I took the insides of a flow restrictor and put it in the ro tube leading to the gauge and then uses a tap to reduce the flow even more. Reads correct tap pressure 2 Bar and reads with a steady 6 Bar on the exit of the pump, no need for a needle valve. Needed to add a support as the gauge would rotate down, think I made a decent job of it. All is good in the world.
Thanks for the info Reefer just added a bit to it.

 

[Reefer Reboot]

Great news I have got the gauge to work. I took the insides of a flow restrictor and put it in the ro tube leading to the gauge and then uses a tap to reduce the flow even more. Reads correct tap pressure 2 Bar and reads with a steady 6 Bar on the exit of the pump, no need for a needle valve. Needed to add a support as the gauge would rotate down, think I made a decent job of it. All is good in the world.
Thanks for the info Reefer just added a bit to it.

Same basic idea. Glad it worked out for you.