Last week of Flowering and I see this in microscope

I just re measured and adjusted the lighting back to 18-21" as well as dropped Temps 3-5f for Terpenes this last week and put new evaped tap water with benes.

My question is what causes sugar leaves to brown? I was getting a lot of brown leaves. Was it the fact the water was likely full of salt accumulation and low nutrients along with daytemps of 82-84f?

I’m sure all of those could have contributed…thinking about it.

I am starting to see the leaves turn snowy white after these changes :3 definitely not looking like mold now.