Hey Rook, great job and +REPS from me, too!
Nice recovery going on the gnat issue and your girls are looking great.
I do agree the other posters on the sand issue. I probably would have used perlite or vermiculite, but that doesn't mean you'll have any problems and I'm anxious to see how it works out.
Finally, IMHO, this bud looks great but was harvested WAY too soon:
When she gets ready for harvest, the majority of those white pistils will turn reddish-brown and, rather than protuding from the bud the way they are in the pic, the bud will basically develop around and encompass those pistils so they appear to be "absorbed" (for lack of a better word!) into the bud.
I do always recommend taking samples at different stages of flower so you can judge for yourself the best point in time to harvest. That being said, the buds also put on about 20% of their weight in the last couple of weeks of flowering, and one of the biggest "rookie" mistakes is harvesting too early.
Try letting some of your plants go until those buds fatten up and absorb the pistils which will have turned mostly red, and the fan leaves start yellowing and dying off as the plant is telling you that winter is close (or, it thinks winter is close!) and it's time to harvest!