Heh heh, you could beat someone to death with those beasts.
That's nute burn for sure, on the salt buildup side.
To avoid that in the future:
a) mix your own soil. But dont' use JUST perlite and vermiculite- you need DIRT. I like my mix of 30-50% perlite, and the rest half and half plain topsoil and composted cow manure and leaf compost mixed.
b) Before you start on your bloom nutes, flush your plants. I can't do that on mine since I use fish and kelp IN the potting soil to avoid yellowing late in bloom, but it looks like that wasn't really an issue for you. So you can flush.
c)I notice that all your plants are different heights, and I'll betcha the one that looks worst is also the tallest. Salt buildup makes plants look worse, faster when they are near a hot light. So anything you can do to encourage even canopy growth in the future will be rewarded.