I have the same experience with mine. I have installed it nine days ago in my sump with the adapter and the level is still not rising. I have checked the fleece and it had some green gunk on it but apparently not enough. I decided to speed up the pollution by putting the hose of my vac cleaning tube in the return compartement of the sump and siphoning a lot of detritus from the substrate directly into the filter but even then no waterlevel rise. Ive noticed also that some of it passes the fleece and the sump is getting more dirty after a couple of days of siphoning. No matter what I do the waterlevel won’t rise. Checked the fleece repeatedly and it seems to close up the mesh grid. I guess a small tank (100L) with 2 fish and a light bioload of corals and crustacians is causing the delay of advancing but even when I feed a lot of debris it won’t clog the fleece enough , very strange knowing that most problems are the opposite

. I guess it just takes much more time to run it in. Mabe I need more flow. I’ ll keep you Guys updated.