whats this stuff

hello everyone
first grow, working a waterfarm kit with a purple strain, and have some growth on the main stalk base
trying to figure out what it is, and how to deal with it.
ph is about 6.2
ppm is at 500
temp is at 76.2
humidity is at 49.0

<a href="http://smg.photobucket.com/albums/v348/ponseman/testbabies/?action=view&current=online5.jpg" target="_blank"><img src="http://img.photobucket.com/albums/v348/ponseman/testbabies/online5.jpg" border="0" alt="Photobucket"></a>


id anyone could let me know id appreciate it

looks like powder mildew. but then again it doesnt. does it wipe away with your fingers? do you see faint white dusting spots starting to appear on any other surface?

it does scratch away, looks like small crystals, doesnt smell like pm though, it goes about 4-5 inches from base up. and not forming anywhere else on the plant.