That doesn't look like a cal/mag deficiency, just a magnesium deficiency. If it were also calcium there would be small, round, rust looking spots. Since we don't know the pH we can't be sure if it's an actual deficiency or lockout. Irregardless, I would suggest mixing 1 teaspoon of epsom salts in a quart of water and misting both sides of the leaves daily for about 3 days. Even if it's a lockout the plant will absorb the mag through the leaves instead of the roots.