Less stressful way to flush?

Had problems on last 2 grows with flushing. Growing using DWC and last time I went to straight PH'd water. A week later they were just about dead-whole plant went limp-seemed like a moisture problem but the roots started rotting fast. I am tapering nutes down now but wondering if I can use Superthrive and some Organic Activator with the flush? Obviously no nutes, but does it seem ok to use these amino acids?
Should I use Clearex?

do you know what went wrong? because i grow in a dwc my first grow and i don't want that happening to me. sorry cant help you i'am a newbe

honestly, I think it was the molasses. I used black strap unsulphered too. They went from green to yellow to wilting in a few days. I was also taking some sample nugs to test it out, so that may have been it or a combination. Either way, the roots rotted in a day or two-smelled real bad and had a few fungus gnats buzzing around them. Got one just in time. The other had some underdevelped lower buds. I have some Kush about ready now and I am going to taper down real slow. I like my bud snap-crackle-n-poppin anyway,lol.

How cold was the water you flushed with.

don't flush then if you think it killed your plants it is kinda stressful but the plant is about to die anyway I don't use any nute containing nitrogen last 4 weeks and don't flush..I slow dry and cure long my buds always taste sweat flushing is a pain in the ass with more than a few plants so I back off the nutes a bit sooner say a week earlier works for me

I flushed mine with no probs - give them 250ml of normal water and let them use up whats left in the next week or 2...worked for me!

thanks for the input guys. the h20 was 70 degrees. I am going to just keep topping off with reg h20 with a little superthrive and nutralife lowering the PPM by 100 or so a day.