Tips of leaves changing

Possibly more potassium needed or something impacting availability of potassium. See "mulder's chart" for choices on nutes with an antagonistic relationship with K and pH would cause a problem with other stuff before it screwed with K and or see a smorgasborg of symptoms that are confusing and overlapping, which is not the case here. Lushness of leaves always looks paler under grow lights. If they are light green under normal lighting you may need a boost to overall concentration, not just K. Light damage occurs at the top of the plant, not bottom-up. Safe to rule that one out here. Plus you r leaves are perky. If they are blasted with too much light they will often droop - especially the last few hours of the day. Again, light damage will start at the top, not the bottom.

Too much light, the leaves should be much darker

LEDs?Is it warm enough?Im English,lol.Whats 68?around 20.I keep mine above 27.I think that's around 80.Its getting late and brain seems foggy for some reason.

You have to put up a diary for that man, burned edges can appear for several reasons. It means the leaf/light/heat ratio doesnt fit at the moment and they burned. That could be because its to hot, light to strong or it could be because your leaves are too weak, because of pH, underwatering, underfeeding. Your plant and soil looks dry tho, probably underwatered/underfed or wrong pH so it cant drink the water, even if you feed right amounts