This IS frustrating. when you knew less what did you do that worked? You've got everything exactly the way you should as far as your nutes, ph, and water. How often are you checking your ph btw?

Can you tell me what your room temps and room humidity is? The last thing I can think of is how warm is the water your plants are in?

If you put in at 310 and its now 290 then yes, they are eating. How often are you having to add water? And when you do are you adding 300ppm water or plain water?

Next set of questions....what kind of lighting and how close is it to your plants?

There is something here that is missing.....but I can't figure out what it is. Any info you have helps....even if you think it's not useful.