OK, I'm short on time here, I am at work. So I'm going to say this and move on.
In RDWC, Coco, Rock Wool - if the plant is growing fast, you get more leaves. More transpiration. More water up the stalk. More nutes with it. Not a higher concentration or ratio, just more overall because they are in the water.
If you then double your EC trying to "help the plant grow faster" you end up burning it. Or N tox. or or or...
The rate of plant growth regulates the amount of water they suck up.
Nutrient needs change throughout the grow - that's not what I am talking about. At a cellular level, you want a specific amount of water and a specific amount of nutes to be delivered to the cell. If you change the proportion of water to nutes by increasing EC, those nutes get stranded in the vegetation which causes burns, imbalances, etc.
What you want is for the plant to drink more in a day to supply the new growth, not to up the nutes ratio in the water. This is self managed by just how much leaf surface area the plant has assuming the environment is not a factor. Remember, you want 6H2O in that photosynthesis equation, you need to match the nutrients to that amount of water to deliver to the cells. Let the plant decide how many H2O molecules it needs naturally based on transpiration, which is based on leaf surface area.
By me needing to raise EC in fog over what I would typically run in RDWC, it's telling me that something is inherently different.
Yes, the plants grow faster in fog. But the amount of water being used by the plants is pretty much linear between RDWC and fog - plants at the same stage with the same amount of vegetation drink the same amounts. So by my way of thinking, EC should be about the same. But they are not. So something in the delivery is different. Is it because certain molecules do not get carried by fog well? Is this about tuning the micron size of the fog droplets to account for all the different molecules? Are my ultrasonics at a bad frequency that has harmonics that hurt the capacity of some nutrient carrying capability? Do I need multiple size / frequency disks to get iron to become airborne as easily as calcium? If this turns out to be true, I need to re-learn my nute mixes completely, or adjust the delivery to be on par with standard hydro.
Now add to all that I am super oxygenating the res well above anything that has been tested.
Dunno. Like I said, I cannot yet explain it.
This is the kind of thing I am referring to