bud luv ... i just got the waterfarm system. i was so excited after i set it up and a few days later i already had roots coming into the 2 gal res.
however, my problem like yours was the ppm in each module. i saw your diagram and i looking to do something just like it. i am confused on your sketch ... do u have the sub. pump in another module? would an inline water pump from the last module to the back of the 8 ga. res where the check valve is be better? i am stressing over this i have been taking time off of work to try and fiugure out how to keep everything constant. i thought this system was the answer, but it seems tweaking is definately going to be necessary. any help would be great.