Those hydro store nutes are industrial strength. You really do need to add sparingly. The new growth DOES look good and that's always what I like to see. So mb it needed Ca and Mg but I'm sticking by my guns and those older leaves were def burned. Its difficult to see bc the picture is so yellowed out. Anywho its good to remember that you're growing a weed and the plant most times will bounce back from abuse.