My opinion on the grow and what I would do immediately would be to raise the lights to atleast 20". Repeat but they say 1000umoles at 12". With autos especially you want to be much lower than that. You will also get a pretty horrible spread at 12" nevermind 8". You can grab a hydrofarm par meter from amazon for 120$. Well worth the money if your in doubt and if your running allot of light.
Next is a sort of controversial suggestion even though I'm positive it would help, is to add a significant dose of calmag. I ran into stunted growth, burnt tips, slow drinking just about every problem till I increased the calmag. I even spoke to a rep from a nutrient company and he said the same thing. When in doubt give them a hefty dose. Photos have a slower metabolism while autos form and produce so rapidly. The calcium is mandatory in plant growth and needed even more with autos especially under leds.
I'd raise the lights to 20" and add 1tsp per gallon calmag and you will be one happy guy I guarantee it.
My before and after calmag solution.
'This was with the regular 1/2 tsp per gallon.
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1.5-2 tsp per gallon. Green healthy and perky.
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