Dirty filter tubes?

[Ghostshrimp55]

This may be no-brainer for some but, as this is my first canister filter I'm wondering, is it normal for things to grow and/or adhere to the inside of the inlet and outlet tubes of a canister filter? I have some kind of "scum" adhering to the inside of the tubes. I don't know what color it is (I'm assuming brown) since the tubes of my filter are transparent green. I have an eheim. The filter is moving water full tilt so there is no restriction or standing water. Just curious if this is normal. Also, is it something that should be cleaned or will it go away?

Thanks

 

[telecubby]

its common ,they have hose brushes that can clean the inner walls of hoses. the scum that builds up also decreases filters flowrate.i'm not saying everyone gets it but get it after awhile ,it took years & years to get my 1st buildup but now its there in no time(could be signs of a good tank though this is an assumption) As long as its not hindering filter performance or flowrate to a noticeaqble degree I would overlook it unless you hate it.See if you notice a difference after cleaning. bamboo rod or skinny pole with a thin rag around it may work,you can push it out opposite end if it gets stuck, this ghetto technique works great. it's messy, theres always more than what looks is there,gl