It sounds like you have set it up according to the instructions properly. What size tank is this on? What is the distance from the bottom of the filter canister to the water level in your tank? Is there anything else installed in the intake/output hoses like a sterilizer, Quick Disconnect valves, etc.?
If your concern is that you are not seeing debris and fish poop being drawn into the intake, you may need to adjust the spray bar direction to 'push' stuff toward the intake strainer. Is there any chance you can post pics of your setup?
Eheim Pimpette #270
Eheim Pro II 2028; Classics Series -2215, 2217, 2260, 2262; Pro 2229 Wet/Dry