I currently have a DWC grow going and I had some slime issues but didn't have time to get the materials and make the "tea" that some suggest. I did some research and decided to try Voodoo Juice, Tarantula, piranha and sensizym (all from advanced nutrients) They are very expensive, but I was able to find a guy that sold them in smaller increments on Ebay for much much less than full price (just search advanced nutrients on ebay, you can build your own bundle). My slime and root rot issues cleared up almost immediately (overnight it was gone) and the roots really took off. I had to buy some more voodoo juice because it needed 1 oz per gallon, but the tarantula and piranha should last me through this grow. If you decide to try it, make sure you get the new formula as it takes less product which saves money. I was amazed what this stuff did.... my roots went from a pretty pathetic amount of shoots to what is shown below.
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Now, about 2 weeks later, the roots are 3 times as dense as this picture and are healthy white with no slime. They are starting to fill the bottom of my bucket! I also noticed that there was slime building up on my air stones and air lines... that is gone now as well. Just a matter of preference but it has worked wonders for me. If you want to see the crazy results of this voodoo juice stuff... check out this dudes video... mine is on its way to being this kind of root system.
http://youtu.be/zy5Fd1rLD0I