Rock hard, gritty, brown growth speckles in my reservoir.

I've been growing all sorts of things for a long time now, but I have never seen this before.

I grow in a DWC system and use these rocks to weigh down my air hoses (never been a problem before, and I clean them well, so the rocks themselves are not likely the cause). Well, these little speckled growth thingies choked the life out of my hoses and killed my plants (I couldn't figure out what was wrong until it was too late). They actually developed everywhere air would come out of the hoses and plugged them up completely (not a single bubble was breaking through). When I rubbed them I could feel countless little gritty pieces, as seen on this once white and smooth rock.



Every single hole on every hose was plugged, every rock was covered, and it was even on the roots. It was tough to clean off the bottom of my reservoir too.

I notice the same thing in my other system now as well (I run two) and this one is about half-way in with 4 more weeks to go. It's hard to get up under there (6x4' heavy top), but I was able to rub down the hoses and get them working again. It's going to be tough to stay on top of it, but I need to know what these are so I can prevent them in the future.

Any ideas? Are they living organisms? Would H2O2 prevent them? I've never used it before (it would kill my organic nutes), but this problem needs to be addressed, one way or the other.

thanks!

bump.. i gotta figure this out

Holy $#!^ That is really unusual...I feel for ya man; The only thing I have to offer is that maybe if you recently changed water, or nuts, or seriously anything that may be the cause. Do you have a camera with a better resolution so you could get a closer pic? That might help. Also if you want an alternative to H202 that suppose to be organic try green cure! http://www.greencure.net/

This looks like some type of micro organism or bacterium, honestly I would sterilizes the unit probably with a very heavy bass.

Heavy bass? These things were hard, like coral rock. They seemingly love the oxygen.

Perhaps this was a result of the Purple Max being added. it warns of rapid growth if you've got something bad growing in there already