Looks like mine when it’s time for cal mag, or something with some calcium and nitrogen in it too. I’m running Lucas, RDWC. Just saying that because I can prob go threw my photos and find that exact thing, maybe it’s just vegging but I bet you will see something else happening pretty quick somewhere. 40 some days in, I have had to add nitrogen and calcium 3 times now running 8/16 on 65-70 gallons, think my ppm is around 900 right now on .5 scale. Check my post history if interested, have had some recent discussions regarding what I mentioned.