All BB set ups should have a control bucket(for one or ten)the control bucket size will depend on how many BB's you have going and how your add back procedure is done(i use a float from r/o which is always adding water).
Using a lil pump to circulate makes your DWC into a RDWC and is highly recommended(i also use a chiller which splashes back into the res/control bucket for added DO.
All BB's with plants also have an air disk,if the air goes off the waterfall and water pump will work alone as will the air if the water pump fails(neither ever did).
I have an online ppm/pH meter on the wall and all i do is read it everyday and add in a lil nutes to 1200ppm.
BTW,i grew for 4 months without EVER changing the solution,during flush i did twice.
