You are damaging them by having them at 24/0 after mucking them around with 12/12 and 20/4.
Just leave them at 18/6.
If you are going to have a diary, fill it out completely, you have no info about fertilizers, soil or coco etc and this info is needed to give solid answers.
Your plant looks like it is suffering from major nutrition issues, pH issue, salt build up, quite a few things, but without more details, it is impossible to be more precise.
Cal/mag is not the solution to every cannabis growth problem, unfortunately.