That's the bee's knees right there!!! That's what I do also...run the flowering tables at 1400 ppm and the mother table at 1600-1800.2 weeks. I use a perpetual system where clones are coming and going from my cloner. So, evry 2 weeks i change the water no matter what stage they are at.
I rarley grow from clone (it stops the evalotion of the plant) but no matter what stage I am in, for the past 11 years I ALWAYS change my res once a week (sundays). I have never had root rot or any other sickness.How often do you change out your rez? and how often do you change out your cloning solution?