I cant tell what this is. Started out as white hairs. Then green spores into what's below. I had a fubar with my co2, so there was a day of no co2 into the tank. Nitrates are around 40ppm, no ammonia or nitrite. Ph 6.6
will kill mold like that (assuming that it is mold). I had a bunch in my tank, and it was killing my plants, and the fungus cure took it out after it's 2 day treatment cycle. It will turn your tank electric green for 2 days.