I dont see any drippers. Is this before you added them. Drippers go in the end of the tubes and drip very slowly. Those plants look like they are getting a high tds (to many ferts) but most likely do to the fact that they are over watered as apposed to your mix is to high in the NPK department. You may want to put them in soil or put your watering system on a timer untill you get drippers for your lines. 15 min every 4 hours may work with your setup but it is a new method to me in terms of how much water is pouring out of the tubing. Do you adjust your ph? I ask because that is why your leaves are dieing. It may be do to your medium such as the rock wool collecting to many fertilizer ions. The roots need air. Your rockwool also needs to be flushed with water and a bit of H2O2 hydrogen peroxide. I would use one tsp or 5ml per liter of 2 % pure but get a second opinion. Do you have an algae problem in your res.?

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