Huh. My bottle of ST says one drop. I is confused. Be careful with that stuff- it's IMHO best reserved for soil growers to use as a transplanting solution. It is primarily meant to reduce the stress of moving a root ball into a new home.
But since you are going into flower you need to completely stop using it anyway. It actually hurts bud-set with all that N and hormones. I'd change the res completely to remove all ST from the system. I'm glad you are getting some easier fertilizer to use!

Yup, a node is the bump on the stem where each set of leaves comes out.