Well, apparently I'm not over the hump yet...there has been diatoms on the sand since the last update, and some cyano starting up again. Those patches of hair algae that were starting up two weeks ago have grown now too. So...apparently it is still a toxic waste dump!
I should test phosphate today to see if my GFO is burned out already. I tested nitrate yesterday, and saw just a hint of color in the water...so maybe 0.1 ppm? I tested in the morning while the sand was still white for a better test. I'll do a waterchange today too. Potassium has been up to 400 ppm for a week now. I don't see any changes yet.
One other thought is I recently switched back to IO. I have done one waterchange with 50/50 IO/H2Ocean, and one waterchange with just IO so far.