You flush for 1 week prior to Harvest with just plain PH balanced water.. The most accurate way to tell when their done is with a Jewlers loupe or a digital USB microscope with a 300x zoom, the 100x will prob work fine though

I have an advice/reference guide on a page in my thread (not sure which page)... and it details pics of Tricomb stages and colour change etc... I think (THINK) lol the best time to Harvest is when 50% of the trichs are Cloudy and 50% are an ambery orange, and the hairs will be mostly orange/red. Your prob right about the plant drinking more water than nuits, either keep adding water or upon water change add 10% less nuits to the RES. ....... Which brings me upto,,,,, When you do your final nuit based water change cut down to about 50% nuit strength and kinda ween the plants off the nuits... then in the last week flush with just PH balanced water, and then LASTLY 48 hours of complete darkness before cutting them down, The darkness makes the plant believe it going to die, and in a last bit to get pollinated, before its life is over the plant will produce another wave of THC/CBD which works out pretty well for all us stoners

Hope that helps man - STELTHY