Strange growth in single part of watercooling loop.

Heya guys!

I'm really, really confused. My watercooling has been slightly noisier than usual for the past while, and I didn't think anything of it until I was refilling it and noticed that it's got... something... that looks kind of like a polymer... growing in one single section of tubing. I repeat, there is no sign of anything anywhere else - just in this one bend right before the pump. All the other tubing is perfectly clear, and I have a killcoil, so it shouldn't be algae, right?

Any help would be, as always, appreciated - I imagine someone's run into something like this before. Pictures in the spoiler below.
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img_20140110_022111_by_darksable-d71lgl8.jpg


img_20140110_022117_by_darksable-d71lgl0.jpg
 
Very glad to know that it's not biological - will definitely drain the loop and do some cleaning. Any advice on how to clean my pump, or should I just not even try?

Haha, sorry manofchalk - I kinda went crazy and wanted some more radiators in anticipation of my next GPU upgrade which I would add to my loop, so that poor little prodigy was stripped down and is now a media PC / steambox while my rig was moved into a Caselabs. I'll take some more pics over the weekend and upload them, though, if you're interested.