OK so my plants are in week 6 to 7 of flower. I'm seeing what I thought was a potassium deficiency. The nutrient line that I am using is Remo Nutrients. I added an extra bit of Astro Flower (which has the most amount of "K" in it) to the last couple of watering top ups. DWC.
i wanted to add if your going to grow monsters like that cal-mag is a must start to finish .... also soil fertilizers like Gaia green are best for monster grows.
buy cal-mag and use it. Check Water PH at drain off after the plants get the water...both just water and also what the ph is after a feeding same spot.... you might need to adjusts ph (plants cant eat if its off more or less)