Hello Rye,
Water softeners that use salt still leave residual amounts of salt in the water. That salt is toxic to plants. Also I forgot to ask, by your reply it sounds like you think your water source may still be high in iron even after going through the water softener? Or do you mean high in iron before going through the water softener?
All you need to check both the water temperature and air temperature at the plants foliage is a simple $2
nutrient%20Solution%20Temperature/thermometer.jpg" target="_blank">glass aquarium thermometer. The new pictures don't look any better, most of the plant's look like nothing but stems. Honestly it looks like something ate them, perhaps even grasshoppers that can sometimes get in the house.
Are you saying the water level is 1/2 inch below the the baskets? Why does the rockwool look so wet/saturated if it's not touching the water? I attached three images of what I was specifically looking at.