Hello Bigdaddy216,
My first thoughts are the humidity is still too low at 45%. 65% to 85% is much better for the plants, you just want to stay under 90% as long as you have good air circulation (which the plants need anyway). But I have a few questions that could be other potential issues:
1. What is the pH, and are you checking it daily?
2. What
nutrients are you using and are you fallowing manufactures instructions (other than 1/2 strength)? Do you have a link to the nutrients?
3. You made a reference to salt "
maybe it because I added some more nutrients and pinch of salt." What type of salt are you referring to? Salt (sodium chloride) is toxic to plants. However Epsom salt is is different. But unless the nutrients your using require adding Epsom salt, that's unnecessary and could raise Magnesium levels to toxic levels as well.
4. How are these plants being watered, and what is the water level in the buckets?
5. If they are on a timer, what is the on/off cycle?
6. Is the top of the growing media moist or dry?
7. Is there a chance there is any tiny water droplets getting on the leaves.
8. Are the plants getting good air circulation?
9. How old are the plants?
10. What is the
nutrient solution look like? Is it clear or cloudy? Does it smell bad (musty)?