Hmm, I just got a 2026 a few days ago and on full blast it creates a very large current and will push the fish all over the tank. I had to cut the speed in half. Of course I have a 55 gallon tank. I'd make sure nothing it stuck in the tubes that are connected to the trays where the filter media goes. That and makes sure nothing like a piece of media got stuck in the i/o tubes. That's the only thing I can think of at the moment. Maybe someone has the exact model can answer your question.
I have one too - I had a couple of problems when I first started to use the filter. The manual is not the clearest.
IMO buy only the ehiem filter material, make sure the final floss is positioned outside the handle and that the green panel is placed on top. Also
Make sure each of the interlocking pipes are connected correctly and ensure the final interlocking pipe is correctly connecting with the motot unit - I found the pipe sometimes failed to meet the motor unit - I think it is becasue the interconnecting pipe can fall into the other interconnecting pipe - hope I am making my self clear?
Trusting you are using the right media, and that the trays and hoses are aligned correctly, you should find that filter will blow your tank apart on full flow (lol! - it does to mine)
Check the ball for flow rate, and check the lever between the two hoses for positioning. Fully depressed, the filter is in full flow - you lift it to reduce output.
