first and foremost, your soil pH MUST be between 6.5-6.9, this is the runoff pH. Your seeing the effects of wrong pH and stop feeding, DO NOT feed until the 5th node or 30days, that is typical. You need to get that pH down first and see how your plant reacts.

Soil pH testing:
Test water prior to going into the medium, add straight water to the soil and catch the run off, test that soil and see where your medium is. You will then adjust your fresh water to the correct pH to lower your medium and then run that water thru your medium until you read 6.5-6.9. Your plants will react to that within the first 24hours.

Also, just feed your plants straight water, no superthrive or anything

Your soil being 50% peat is WAY to hot (meaning that the ph will be too high for your plants) You need to change that soil mixture, take a look at Stinkyattics sig, she has a nice recipe there for some medium that will take care ALOT of your pH issues right from the start.

In your second pic that you posted, you can see that one of your plants is just about dead due to the pH being so high, that plant mostlikely is beyond recovery, so you might want to pull that one out before it causes more problems for ya.