I admit, I got to the point of cussing out Rena under my breath. I just spent 3 hours trying to get flow out of my XP4. I read every FAQ, re-read the Manual, watched the video again and nothing seemed to help. I re-did the baskets 4 times. I tried priming with the filter empty and with it full. I tried everything.
Then I thought, maybe one of the tubes is plugged with something, so I tore it all back out. And...noticed I had a twist in the tube. It was twisted and doubled in half (on the exhaust tube).
Once repaired, of course now it's pumping water like crazy :)
Its an awesome filter...thank you Rena!
(oh, and sorry for the things I said lol ;)
EDITOR NOTE: It is usually the most obvious things that cause flow problems but we forget sometimes to think logically since we get caught up in the troubleshooting aspect of fixing the filter :-D