Brown dry leafs..

I have tried to find pics like this to help ID the issue.. but. here i am. I don't want to guess and be wrong..
First..
Jack Herer on soil.
Was grown on FF grow big/cal mag with 6.5ph

Next to this plant is a durban that is just as happy as can be.. same feed and all...

I have had leafs like this on the herer but thought i had it fixed, but found a few more tonight.. thanks for any tips.

P.S. i have a bad habit of watering through the top of the plant.. so there is some residue on other leafs.. i have stopped doing that mostly now..

Looks like too much fertilizer

Bad habit to get into and resido will spot kill a leaf
U can see in the very low left corner I seen the drop there left it and 2 days later .
Dead spot

Thanks guys, and yeah i was running way to hot on my nutes.. i got a ppm meter 2 days ago and have a better idea on that now.. plant seems happy enough other than that, thanks for the help..

And no more watering through the leafs...