Whatchu think?

I'll provide some grow details if need be, but just at first glance/instinctually, whatchu think this might be?

Leaves seem to be browning/rusting/call it what you will, from the center of the leaves outward around the top colas of some of branches, and the affected leaves are dry and brittle.

Any chance u spilled something on the bud? Is it just one or is it on all the tops?

Hmmm how far are u into flower? Might be cal mag but it’s only on tops.....any chance u had hand sanitizer on your hands and handled a few tops?

Maybe getting mag hungry? Got any Epsom salt....gram a gal.
FF

No chance of spill. Nah, don't use hand sanitizer very often. I'm about a month into flower, growing in ocean forest running GH nutes at about 50% strength every other water. been pHing to 6.8 as that generally does well in OF but thinking might be a pH issues, possibly iron lockout as it's one of the first to show when soil goes alkaline, and 6.8 is fairly alkaline.

Running RO water with calmag added every time I water but could try upping the dose. Usually when I see random shit like this when I've changed nothing since my last few successful runs I think lockout of some 'random' element due to pH.. about all I can think.

When in doubt flush them out...I agree with lock out try lowering your ph to accommodate iron uptake if u still see Symptoms progressing after two weeks it’s not iron lockout I grow and Coco and I ran into a horrible Cal mag deficiency I bumped up cow mag to 350 P PMs and slowly got worse over the course of two weeks then out of nowhere they bounce back and blew up when you run into deficiencies they’re not cured overnight it takes one to two weeks for them to correct them selves so if it is iron give them two weeks symptoms progressing after two weeks it’s not iron lockout I grow in cocoa and I ran into a horrible Cal mag deficiency I bumped up Cal mag to 350 ppm‘s and slowly got worse over the course of two weeks then out of nowhere they bounce back and blew up when you run into deficiencies they’re not here overnight it takes one to two weeks for them to correct themselves soffit is iron give them two weeks If it’s still getting worse after two weeks check back in we’re all in this together