Here's an observation, for what its worth. My first couple runs, I had a lot of powdery residue on the walls of my res. I just cleaned my res for the next grow and there was very little residue. Some yes, but not much. I believe this is due to mixing the solution well. I start with a 1L jar that I use for a shaker. I ad about .75L and the amount of Megacrop I intend to use. I shake it real well. using a paint stirrer made for a drill, I stir the water and ad the mega. I then mix it real well for 2-3 minutes. work that stirrer up and down good. and that is what I believe did the trick.
