Leaves clawing down

Hi. Try to keep 25 degrees celcius. Yes if is to heat bring lamp up and put more fan.

Not a lighting issue, it is an over feeding issue.

Hi bud. That looks like a typical nitrogen toxicity. Often due to bad watering habits. Still trying to get this one down myself.. Hope this helps, even just a little.

500umols is a good place to start in early veg.

I would of been saturate=ing my pots 2wks ago if I were you.The roots will be bigger than the plant so you'll have certainky got some dry back on the roots with not soaking it.That could be the issue.Theres a free app to measure your light.I use PPFD Metre.

Groth nodes at the top have decent spacing, so i'm not so certain this is due to too much light. watering habits look suspect due to drying pattern, but can't be certain from a static picture. 1) fully saturate, never half ass this 2) appropriate dryback and repeat simple as that, don't complicate irrigation. If soilless, religiously get 10% runoff, too. Thinner leaves in new growth can be indicative of high P or K levels - it should also coincide with some slight chlorosis of new growth, too. Re-assess your formual and adjust. Clawing is often associated with N-tox, but these leaves are not overly lush or glossy to the point of causing such a symptom... i think it's jsut from being slightly overfed in other areas. if your irrigation habits greatly deviated from the above, that too can cause some wonky levels of nutes in your substrate. if that is the case, i'd fix irrigation habits first, then see how that impacts things the next 7-10 day before adjusting -- this assumes nothing negative is progressing at a fast pace.. if patience is plausible, stick to it. if it heads down hill fast, you make the best guess you can and live with the forced early decision before you are confident about the cause.