Hey Smacc looks good a little browning but lets look at the big picture you have "bud"
I would rather see some browning then none at all it means to me you are challenging the plants with nutes, next round you adjust accordingly it's that simple.
I don't know what size tank you are using but it may be worth your while to pick up a second tank to have on reserve just in case you run out. I learned this the hard way running out over the xmas holidays boy was I mad, also the bigger the tank the less you pay I pay $40.00 to have mine refilled and that 50lb tank will do me a full flowering and then some.
Flushing is up to you I prefer to but it may be in your interest to take a small sample before you make your decision, try it first hand and guage it from there. I also turn my plants upside down for 24hrs on coat hangers to let whatever resin is in the plants flow to the buds, old school perhaps but it's my preference.
You should be very proud of yourself dude you did a hell of a lot better then I have on "3" grows. Make note of any minor mistakes you made and correct them next grow each strain is different so stick with what you know, I would wish you luck but you don't need it keep up the good work.