Strange Brown Spots Forming On Top Fan Leaves

New ph meter is in I fed today at a ph of 5.7 runoff came back at 6.3 cause for concern?/what should I do?

I just uploaded a new video of the brown spots without the purple light to my grow diary if you could check it out that would be much appreciated thank you everyone for your help!

Thank you everyone for your help I'm going to try these options and see if they work. Just got my new Apera PH meter in going to do a feeding tomorrow and check the runoff to see if the PH is right. I'm getting a TDS meter tomorrow as well so I can also check to see if I'm giving enough/too much nutrients. I have splashed some of the feedings on my plant accidentally and also got a little DE on the leaves it may just be coincidence but when I switched the bloom light on I believe the spots started to appear, the bloom light on also raised my temperature up to near 90 degrees and I had a high night time temperature too of around 88, I've got the temperature now under control but the spots seem to still be increasing so definitely thinking its some sort of lockout or deficiency.

It is nothing, no plant will ever have 100% perfect leaves, 100% of the time. If they are continuing to grow as expected, why imagine non existant problems? Most likely dots from water droplets/condensation when the lights are on, causing slight burned spots.

Did you do a foliar spray with the light on? Could be burn from that? Or a spilled few droplets ?

Nutrition demands on your plant is changing. It is one of two things. Your ph in your soil is changing to a lock out position or your plant wants more nutrition. Easy on nitrogen. You look very heavy on nitrogen.

Im guessing a calcium deficiency maybe kinda hard to tell

Hard to tell with the burple on. Did you spray your plants.Could be light burn from droplets