I myself had dealt with this same problem in the past and I know how frustrating it can be. I would do lots of water changes to try to combat it but in fact this actually fuels it. Here is what I did and it took some time, but it worked!! Keep in mind that you are not going to rid your tank of this overnight, it will take some time. Once I had gotten a hand on it, it still poppped up here and there for months afterwards. NO PRODUCT WILL WORK!!!
Buy yourself a phosban reactor and fill it will a small amount of GFO to start, then increase over time. I found that this along with cutting a couple hours off the light cycle per day (for a week or two) began the process of removing the junk completely. I did do a couple of very small water changes every couple of days just to suck to junk off the rocks. (a couple of gallons). Once that you have seen that is is going away, then you can start to do large water changes. I also thik sometime that this crap is some type of a cycle and goes way over time. Anyway, GFO will do the trick. Again, it will take some time though.
