Right on. My No3 is and has always been pretty low in this system. Like undetectable and it only rose to .25ppm at its peak during the treatment. My Po4 went from undetectable to .16ppm, but I have slowly lowered it to about .02ppm with water changes and GFO running in my reactor. I hope that running the GFO reactor this entire treatment will keep it in check and cause the algae to succumb to the treatment!I don't have the hairs of it sticking up but do have the roots and the roots are spreading so I'm in a similar situation as you. I do think that they're spreading because my no.3 is very high. And has been from the start. I believe that if my no.3 was quite low in the first place it would have killed it off completely. And I also believe that the second dose was pretty much worthless in my case because my no.3 is still too high. At least that's what my situation seems to be. I believe the NO3 fuels the root system. Best of luck to you ! Oh and I did not get cyanobacteria at least not the red kind. I do have some green in my Sump and I've noticed a few spots here and there that are very very tiny in the DT