I just got my pond installed at my new house. I bought a new 2100 gph pump and a pressurized filter that is sized for my pond. I used 1" hose as recommended. My pump pumps water like a fire hose until I connect it to the filter. it just comes out slowly. If I turn the filter to discharge it comes out like a firehose again. I had to put my old pump and filter from my old house so the fish are ok. They all look happy and I am getting the plants in this weekend but need to fix the filter issue soon.

So something is wrong with the filter but I don't know what or is there something I can do?