Nice looking setup there, I'm subscribed. I also liked the link to the other grower that didn't even use nutrients... crazy!
On most LED grows I've seen on YouTube and such, the growers have the plants really far away from the plant, and you can see that it's causing the plants to stretch. I think this is where the stretching stereotype comes from.
You've found that you like them 12" away, huh? What benefits have you seen from that? I've always been under the impression that the light source should be as close as possible to the plants without causing damage, especially when heat is no longer an issue. Is it a cross-lighting thing? With a narrow light angle, I can see how that could play a role. I still don't imagine myself putting them any further than 6". Double the light distance, 1/4 the light intensity (see pic 1, light intensity vs. distance).
You mentioned that your LED setup has some "full spectrum" LEDs. I'd be wary of that claim. LEDs, by nature, are very narrow in the color spectrums they emit. Bright White LEDs are almost always a combination of two colors that ends up looking white to us, when it's really a mixture of something like blue & yellow. (see pic 2, color spectrum of a common high-powered 1W White LED)
There are a couple of nice things about the white LEDs, though. They make it just a little easier to see in there, and they do level out a little bit of the center colors by having that yellow/green accent. The panel at least has some light in all the colors, so I guess you could technically call it "full spectrum."
It definitely looks tough to compensate plants that germinated at different times, came from different strains, etc, etc. I bet you're looking forward to a grow with your clones where you can start one type of plant from one mother at the same time, multiple clones, all on-track with each other, not strangling each other out. I look forward to seeing your LEDs on that, too.
Whoever was asking about Lumens, they don't really matter, especially on LED setups. Lumens are a measure of how bright the light looks to us, which is entirely irrelevant to plants. We see green the strongest, they see very little green. That's actually why the plants appear green... the plant reflects the light it doesn't use, so that's what we see.
I've been working on creating a custom LED setup, and a big focus has been on having LED colors across the spectrum. It involves 1654 LEDs. I'm excited. Here's the link, if you're interested:
https://www.rollitup.org/indoor-growing/186051-my-lighting-project-will-custom.html
I'm glad you decided to pluck the male nodes... I was really looking forward to seeing this grow through to the end.
Dr Greenthumb was talking about not needing an airstone because his clones weren't touching the res water. The way I visualize it, pumping air into the water means you're also pumping new air through the airspace in the res... new oxygen for the roots? Perhaps the difference is negligible, but air pumps are cheap, and it couldn't hurt. Any thoughts?
You started off with some great updates on pH, ppm, etc, etc... that's a great way to post your updates, can we get that again? Several of the leaves looked like they were showing slight nutrient burn a couple pages back when you were at about 900ppm. Curled tips, light browning on the edge of the leaves. Have you bumped it up to 1200 yet like you mentioned? As before, I could be wrong, I'd just watch it very closely when you do decide to bump it up. (see pics 3 & 4, examples of nutrient burn - 3 is light/ok, 4 is medium/damaging) I've heard some say a tiny bit of nut burn is a good indicator that you're using just enough nutrients that the plants are taking in their full potential.
You know what might be a cool experiment? You could put the 18W blue shining horizontally on one side of the plant & the 55W on the other side... you can compare how each light affects the yield on that side of the plant. It's an idea, anyway. I'm the experimenting type, and it looks like you are as well, with all those different types of grow systems & lights. Also, the extra light may boost water & nutrient intake potential, making it easier to bump the nutes up to 1200.
Overall, an excellent example of a successful LED grow from start to finish. I look forward to seeing the finish.