Hello Rye,
First what is DWR??? Second I cant rule out your water supply until I know what water supply your using. Third often times problems are a combination of combined issues rather than just from a single cause. So it's better to look at and understand how things are related and affect others.
1. What type of system are you growing your plants in?
2. What are you using for the water supply?
3. What are you using for
nutrients, and are you using any additives?
4. How are you mixing the nutrients? I don't mean the ppm, I mean compared with the manufactures instructions. What is the manufactures recommendation per gallon of water, and how much are you using?
5. What is the pH, and does it fluctuate?
6. You mentioned growing three types of plants, do all of them have the same condition?
7. What is the water and air temperatures?
8. How many actual plants are you growing total, and how big are they?
9. What is the total water volume in the system?
10. What is the humidity?
11. is the color of the foliage nice and green?
12. What do the roots look like?
I'm leaning towards saying it's a calcium deficiency in the plant, but not necessarily in the
nutrient solution. So first I've got to rule out other possibilities. Then figure out if there are contributing factors before saying the nutrient solution is lacking calcium. If the problem is environmental, it wont mater how much calcium is in the nutrient solution. If it is a calcium deficiency, even when it's fixed, the damage is already done. Only the new foliage will be healthy.