Quote Originally Posted by stinkyattic
Draining and refilling the res isn't necessairly a 'drastic' move- how often do you switch out your res anyway?
I don't. With the Lucas Formula you're not supposed to, actually. Lucas originally recommended switching out the res when you started flowering, but he has since changed that recommendation and now suggests switching out the solution only if something goes drastically wrong with pH or the ppm's get severely out of wack.

Also, since refilling the reservoir involves bringing home several gallons of distilled water (tap water at my place sucks), I consider that "drastic", or at least a serious pain in the ass lol.

EDIT to add: Also, part of my concern is to identify the underlying cause of the N toxicity. If it's a problem with the res temps, then I know what the fix is. If it's the nute solution, then I need to research more to know what's wrong. Although, I'd be somewhat surprised since there are a LARGE number of growers who just rave about the Lucas Formula. Of course, it's also possible that I'm a complete noob and I've managed to bungle the Formula lol.