Yeah my tank looked like this. You have to just keep cleaning it off. Eventually it will go away. You must keep cleaning. Don't give up =)

it was completely gone for several days after the 5 day blackout (I had like thick blankets over the tank I only removed for feeding)...then it just slowly came back to this..I'm so sick of this crap. I'm done pulling it out ...the smell is like as potent as a skunk, it just sticks to you... I guess I'll try another blackout and instead of keeping nitrates high afterwords I'll do heavy w/c's instead as dizz suggested. I don't know what else to do. I'd consider R/O water but thats not a habit I want to develop since money is getting kind've tight (yes, even for water).

It appeared very soon after changing my filter to an aquaclear 70 which I seeded for about 24hrs with my old bio-wheel, don't thin that was enough, but anyway...the filter was so powerful at full-bore I picked up a sponge pre-filter for it...I'm wondering if when I'm doing filter maintenance the fact that half the crap stuck to the sponge goes back into the water is really harming things...I don't want my fish to get sucked into my intake though. lol

Bleach just really isn't a route I want to take, to me it leaves too much room for error, and as you say isn't a final solution. If I were to skip treating my driftwood with all the moss on it it would just act as a harbor for the stuff to come back from as it already does. If worse comes to worse, I'll remove all plantings, stir up the sand and do a full week blackout followed by a large water change, and several smaller ones. The blackout worked suprirsingly well, there was no trace of the stuff after lifting the curtain so to speak. Something in the water is just acting as a great source of food for this stuff to thrive in I guess. I've started a new w/c regimen today so hopefully keeping nitrates and dissolved organics at a minimal even if it means killing my plants (which aren't growing anyway) will solve my problem. I also removed the pre-filter and wrapped a loose screen around the filter intake so hopefully my finned friends won't get sucked to it.