Interveinal Rust Spots and Dark Veins

Without a diary, we can't tell you with any certainty what's going on here... don't even know what you're growing or how old these ladies are, what you're feeding them and how much... It certainly looks like you've got a deficiency going on here - probably calcium - but unless you know WHY, you won't be able to solve the problem even if you throw a whole bottle of calmag at them. I would first check your pH meter to make sure it's giving you an accurate measurement because often this type of deficiency stems from an improper pH level. It can also be caused by a nitrogen toxicity which locks out the calcium that is in sufficient supply in normal cannabis nutes. So please, start a diary - even if you can only reconstruct the past one or two weeks... it will give us a lot more information to go on and we can then give you a rational path forward... Good luck....