Well they're autoflowering so they don't need a lot at all before flowering. But I added 1/4 strength grow after the second set of leaves was in and the third was coming in, and then 5 days later i added 3/4 strength. After that was when I started to notice the burning edges of the leaves. I don't plan on adding more nutes till I see flowering (which should be within the next 3 days or so). As for res size, I'll definitely be upgrading to a 4 or 5 gallon tomorrow.