RO/DI unit pressure changes and whoosh sound

[Reflective]

So I changed the DI resin in my RO/DI unit yesterday, then noticed now when I turn it on, about every 30 seconds it makes a whoosh sound like air being pushed out. Then just now I was watching the pressure gage, and it hovers around 63, then slowly climbs to 65-70, then drops down quick to 50 when it makes the noise.
It's never made the noise before, and I've never noticed the pressure bouncing around like that. Any ideas what's wrong with it?

 

[Reflective]

Just noticed there is hardly anything coming out of the waste line as well.

 

[AZDesertRat]

Sounds like you have air trapped inside the system somewhere.
While it is operating, pick it up in your hands and slowly rotate it around in all orientations so it releases any air trapped in the housings.

 

[Reflective]

So after testing each part of the system individually, I narrowed it down to my 2nd DI canister. Then after tons of hair pulling I finally figured out the the "universal" cartridge that I used to replace the resin is not so universal.