m0useanswered grow question 12 days ago Yup, just like your last question, and now I see the diary linked to this one. Good Work!
To strong of a feed and to soon.
You fed 1EC on day 13 and then 1.8ec on day 17
Feed em once a week with a bit of runoff to prevent buildup. water for any other needs till next feeding time but do no get runoff.
With RO water you will want a little something in it as its void of nutrients and agressive, so the root boost is good. could even do 1/4 or 1/6ththe strength of the other stuff so its hitting 100ppm or 0.2EC just a little something but not much of anything. My tap water comes out around 130ppm.
Also your light seems very strong, 730 watts at 35" or 90cm hang height seems ok. but what dim setting is it on? Just watch the plants and if they are getting to compact and short internode spacing dim the light more. Would be good to find out your DLI, can ballpark it with PPFD maps of your light. online says its dim button can do 250W, 400W, 600W or 730W. I would email them for recommended hang heights and PPFD maps if they did not come with any. I'd also prob dim that down to 250w for the 4x4 tent. 16square feet, 250/16 = 15w per square foot is good for seedlings. 400w is around 25w per square foot and that's a good amount for veg and flower.
To answer your other question on your diary with the video of the plant. its variegation. Plants sometimes do this when they are young and nothing to worry about, it should grow out of it. If not its just pigment of the leaves and does not really indicate much of anything.