Gracias Em, greatly appreciated. You're right - I was making it more complicated than it is and overthinking it. Imagine that. And for the record, I have basically stopped using the internet for my information gathering. The information you find is rarely consistent, much of it is inaccurate, and the people who write about weed often seem to present what is essentially their own style choices as facts about how to grow. It took me about ten seconds to realize that I will find way better answers and information in here than I will on an internet search. Besides, it's kind of hard to interact with an article and ask it questions. They tend to not respond. Bitches.Don't worry about the old nute leftovers... out with the old, in with the new. Just carry on with everything as normal, just flush instead of plain water one of the days, and on the very next watering give the new nutes. There is absolutely no reason to give nutes or even diluted nutes on the day of the flush. Despite what you may read, flushing and ending up with no nutes in the soil for a few days does not hurt the plants.