FF trio seems to give a lot of people issues from what I see in these threads.
Best advice I can give you honestly, is if you want to produce plants as healthy as MiMed just read through his thread and emulate it as close as you can, and a massive part of his success comes from the fact that he understands the nutritional requirements of cannabis. Feed your plants exactly what he feeds and how he feeds his plants. Nutrient brand can differ but keep the NPK the same and make sure its balanced and complete, and your starting water has adequate calcium and magnesium. It's really that simple. There is going to be a bit more to it and issues will still arise as they do for all of us, but that's it in a nutshell. Adjust the feed rates for whatever media you're in and you're set.