I used the FF line-up when I started years ago. I agree with "smoke and coke" on the need for Cal-Mag. I use General Organics Cal-Mag now and have no issues. I run Advanced Nutes now, and have seen a huge difference in plant structure and yield since the switch in nutes. Fox Farm is good for beginners due to the start up costs, but you may want to start your research on how to take your garden to the next level with a different nute program. You are doing a good job when it comes to using only a fraction of the recommended dosage.
Also, I am not saying to go with AN, but be open minded when comparing nute companies/products and what would work best for you.
The key is to be open-minded, and keep learning.
Happy gardening bro.