I started using MegaCrop on my last grow and I was impressed with it.
It’s essentially like Lucas formula in that you only use the one nite for the entire grow and this nute was designed as a stand alone specifically for cannabis.
I know the company says it’s formulated so that you shouldn’t need calmag, but I can’t really verify that as I used well water that has plenty of calcium in it as my water source.
But I will say that if you are growing in coco I would recommend “precharging” it regardless of whether the company claims it is or not. By “precharging” I don’t mean soaking in nutes, I mean soaking it in water that has a heavy dose of calmag in it over night or even a few days. The purpose is to remove the sodium and potassium charge and replace it with the calcium and magnesium that have a higher bonding affinity.
Usually if you need to use calmag with coco then that means it either wasn’t properly charged or wasn’t at all. So if it isn’t then when you add your usual nutes the calcium and magnesium in it, with its higher bonding affinity, will attach itself to the coco making it unavailable to the plant and in turn release sodium and potassium that will then be “released” into the soil and cause their own issues. Basically it will turn a perfect nute formula into something high in potassium, dangerous levels of sodium and lacking in cal and mag.
So my method of “precharging” is that I take my coco and put it in a container. Then I add roughly 1 cup of calmag to a gallon of water, yes that much. I then add enough water to the coco So the coco moves freely in it and when settled there is at least a few inches of water above the settles coco. I let this sit for 24 hours, stir it vigorously and let it sit another 12, stir again and then pour it all into a big enough fabric pot to hold the coco.
I use a fabric pot simply because it allows the water to drain away quickly and easily and catches all the coco.
I then rinse with water with a noramal dose of calmag to make sure I get as much of the released sodium out of the coco as possible.