Cal/mag deficiency? Burned edges and tips. Rusty dots. Damaged leafs. Began at oldest lower fan leafs, progressed up.

Are you in veg or flower. When in veg it is important to keep your ph as close to 5.8 as possible. When in flower when button sized buds have formed then you switch to 6.2 for early flower, and 6.3 for mid to late flower. Don't know if it's an auto or photo? Autos should be good at 650 ppm max. Photos are usually good with 800 ppm max. Ween your girls off of veg nutes after a first flower feed of half veg and half bloom. By about the start of their 6th week in flower the veg nutes should be weened right off.