Nutrient problems!

You have got k and mag def

Hello I think we can rule out a nutrient excess...just because the tips aren't just burnt, it's going up the edges too. It looks a lot like a potassium deficiency. How's your ph? Have you recalibrated your pen recently just to check its working properly? Also the shiney grey in the background...that's not tin foil is it? If so be careful of heat sinks happening, because high heats can also cause these yellowing. The whitish spots and the bumpy looking leaves I'm not sure...that's also why i think of a ph issue or unhappy roots in one way or another .