Need help. My 2 Emp 400's are barely moving any water?

[ukbice]

Hello, I know this is primarily a saltwater forum, but I just needed some expert advice, so here goes. I have 2 Emperor 400's on my 150 P tank. They barely move any water thru them, do I need to replace something or is there any tricks I could try? The flow is all the way up on both of them. Ive tried cleaning and reseting. I have another one on my 90g and it moves at least twice as much water. Any suggestions would be greatly appreciated. Thank you in advance for your insight! -Josh