Wow, what a learning experience this is! That test was a little one-shot pill deal where you dissolve some soil in the tube and add the powder from the pill.
I will visit a place and get what you suggest.
This "flushing" business. I think I read that that involves adding 3 times the content of the pot in water. Is that right? Or are you saying I shoulld just do a gallong? I have a 4 gallon pot by the way.