if your plant is having problems , and you want to put the breaks on, especally if she is in a serious decline (some sort of nutrient problem) and you are growing hydro, nothing beats filling the resivor with distilled water and letting it run for 48 hours.. this gives the plant an incredible flush and kind of "freezes" the situation.

I have seen plants live on just plain distilled water for 3 weeks. THEY did nothing.. they did not grow.., they did not wilt or die.. they just stayed the same.. they were about 3 weeks old in a hydro system.. and they stayed at this 3 week maturity for another 3 weeks.. and then the same day we added nutrients the plants just started growing again