when I first noticed it was doing that I held up the float valve at the end of the line and they filled up soon as I let the float down it all gushed out. I’m not too sure of the pressure as I don’t have a gauge to read. My old ro unit fills right up and stays filled. It produces a descent amount of water so I would assume there’s enough pressure to get the job done I’m guessing anywhere from 40-55psi just a guess tho. One of these days I plan to add a booster pump and gauge but for the amount of water I make I wasn’t to worried about what the pressure was. I know at my parents my fathers ro unit runs slower than mine and he is running 75 psi he could possibly need to change his filters though. Mine is running fine like it is, steady stream of product water and I’m getting 19tds going into the di, 0 before and after the mixed bed resin. But if it’s supposed to be filled at all times then i would like to figure it out. I’ll try popping em open to purge the air see if that does the trick. Thanks once again for the response as well. Were you able to view the video? I tried to watch it after I posted the thread but couldn’t.