dirt in python

[fishycanuck]

I have had a Python aquarium vac for about a year.  I have noticed some black stuff stuck to the inside of the tubing which looks like mold. I tried soaking the whole thing in vinegar and rinsing with lots of hot water but it didn't shift.
Should I be concerned about this? Is there any way to clean it out?

[mseguin]

My guess would be some kind of mineral deposit, it shouldnt harm anything.

[FishPassion]

All my python hoses are the same and I am not concerned with it as the water is discharging form there anyways. I had thoughts of pulling a brush through it but didnt bother.
Hope u had a Merry xmas and happy new year fishy.