Pictures are bad but I think this is your issue.
What Does Excessive Calcium Do?
Too much calcium in your weed plants can lead to some severe consequences. The most obvious problem that you’ll see if you overdo it with
a calcium additive is leaf burn. The cannabis plant is reacting to the excessive levels of calcium and is trying to push it out from the leaf tips. This causes necrosis (death) of the leaf tips, and they will be a yellow/brown color.
Besides causing leaf burn, excess calcium doesn’t actually create such drastic symptoms as a deficiency. Instead, too much calcium in your cannabis plants will actually lead to
problems in other nutrients, such as magnesium and potassium. This situation presents a very frustrating problem when growing cannabis. Too much calcium will lock out magnesium or potassium, and the only way to correct the problem is by first dealing with the calcium issue.
So, although you’re experiencing potassium and magnesium related symptoms, the actual root of the problem stems from too much calcium. Dealing with an excess calcium problem doubles or triples your work by making it necessary for you to also try and
fix your magnesium and potassium issues. It can also lead you astray chasing other nutrients, while the calcium problem remains active..
Excess calcium
How to Correct Excessive Calcium in Your Cannabis Garden?
Once you’ve determined that you have excess calcium in your marijuana plants, it’s time for
a gentle flush. When I say gentle, I mean a low dose of a balanced nutrient mix. When growers here the word
“flush,” they think pouring liters of water through the medium to flush every nutrient out. This is inadvisable because you’re suddenly depleting the cannabis plant of all of its necessary nutrients to function.
Flushing with
a low dosage of nutrients allows excess nutrients to be pushed out while leaving a smaller concentration. This method allows your plants to continue taking up critical nutrients for its growth.
Alternatively, you can flush your plant with a low dose of calmag,
a combination of calcium and magnesium. By flushing with calmag, you decrease your chances of suddenly locking out potassium and magnesium.