I use Canna nutrients exclusively like you. I only use molasses during flower from week 3 to about 6 or right before I flush and it seems to work for my girls. It will raise your ppm but as long as ph is ok, they shouldn't burn. These are my latest @ week 6 of 9 week run.
Gary Payton
Gellati...
I use a 25 gallon tote to catch sifted material. First I let my used coco dry out with minimal dampness to keep the coco from being powdery. I take a plastic dollar store spaghetti strainer and shake the root ball into the strainer, then shake strainer sifting the small root matter from the coco...
You pretty much want to fill in the space horizontally aka the screen...just like you have it, but with no open spots. That's what they mean by filling an area. Once you're satisfied with the canopy, trim anything beneath it let it recover and flip to 12-12...that's how I pull a little over 500...
I would start something else if possible, but in the meantime cut out any infected area you see and monitor. Keep humidity to a minimum no spraying leaves. I never ran into bud rot so that's my best advice.
I run a 600 watt and a 350 watt (496 true watts) Viparspectra in my 4x4 tent (which is equivalent to running a 600 watt HPS) and I get great buds. Granted light penetration sucks, but that's why I top as many times as I can and when I get ready to flower I trim everything except for two or three...