RENA XP2 question

Hi, this question is for those with experience of Rena canister filters. I've had a new Rena Aqualife tank in cycling for a week now and its well planted and seeded with a little fish waste and fish food in the hope to speed up cycle.
I'm happy with the Rena filstar, the outflow is great and it's very quiet. My question is is it normal that the inlet does not seem to suck up much? Bits of plant and food and waste I added when seeding have just gone moldy or grown fungus or something and are not seeming to get sucked up much, they just float by it if I stir them up. My old small rena tank with a biobox would suck up everything in its path in comparison-Am I supposed to be vacuuming all debris as the filter doesn't handle it? Shouldn't the filter be sucking it up? I've lowered the inlet siphon down lower than than the 4 inch above gravel recommended (is this ok?) and it seems to work a little better now.
Thanks in advance for any help

 

Wow, sounds like something isnt working right. My filter did the same thing, i just took it apart and found the problem. One of the pieces wasnt in place.

 

i love my rena x2 i use it on my 40gal breeder. mine has great sucking and pushing power. i would see if you have somthing maybe in the wrong place or see if something might be blocking the full flow