Mold??!!

[Sniperboy]

I'm noticing some black stuff building up on the part of my barb exposed to water. Would this be mold? I'm using Purple Ice, shouldn't that kill mold?

[[EG]~NaTz~]

it may be just a dirt or resin...

[Stalka]

its black? it may be the Purple Ice drying up...

[Voodoo Rufus]

It could be a discoloration of the tubing over time. Water Wetter tends to do that, especially if it sits a while from my experience.