I think your plants might be suffering ammonia burn. ADA AS releases a huge amount of ammonia over the first couple or three weeks, dosing fertz and LC might actually make that worse by increasing the solute concentration of the tank water.
I suspect what happens is...increased solute concentration lowers the water potential of the tank water and increases the relative osmotic potential of the plant cell. The result is that net transport of water will then be from the plant cell to the tank water, instead of the other way around.
This in turn causes a negative pressure potential in the plant cell which then collapses in on itself and eventually dies or suffers necrosis; melts. The dead plant cells then release more organics exacerbating the situation, and diatomaceous algae results.
I've suffered it myself, and have since learnt that when using AS some folk cycle the tank without plants, no additives nor light, or water changes for that length of time first
https://www.ukaps.org/forum/threads/cycling-without-plants.52187/