Marineland 350 question??

[Donewiththisplace]

I started using a marineland 350 on a fw 55 gallon 3 weeks ago and the inlet hose seems to be collapsing about 2 inches off the top of the canister. Does anyone know what could be causing this.??

At first I thought it was the strainer restricting the flow..but it is the stock strainer and the canister stays full.

Thoughts??