Usually a week of flushing is enough but 2 is what most of us do.
About the only thing lowering temps will do will make them turn purple but usually you do that earlier in the grow. DOn't know if it would make much of a change in 3 weeks. Might be worth a try. I've run them down to about 40 during lights off.
Lights off for a couple days at the end can help resin production. It stresses the plant and it produces more resin in times of stress.

The plants are looking very good.
killerweed420 Reviewed by killerweed420 on . rounding third coming home, we're almost there! Alright if I got you to click on this post because of it's clever title, than this was a success! Anyways, I'm at 6 weeks and 2 days into flowering and I need to figure out a couple things before harvest which should be by the 9th week, latest. First off, ive read a couple different things about when to start letting the plant suck up its own nutes, I'm at week 6 right now, should I start just straight water feeding or wait till the 7th week? Second, is this an ok time to lower Rating: 5