Hey, for your little yellow leaf problem, you need some dolomite lime. It will boost calcium and magnesium, and it's natural. It'll help you a bit and be good for your roots.
I would also say that you have an excess of nutrients. But since you're towards the end, just leave it with water to rinse it a bit and remove the excess. The yellow leaves don't bother me, it's the burnt and dry leaves that are a sign of overdose.