no need to add nutes until the plant[s] start showing a deficiency. agree that ph is ok. Hanna makes good meters ,it was a wise decision to get one.to save $ on calibration solution i bought a case of bottled drinking water with minerals added for flavor ,tested 3 bottles for PH and PPM/EC and recorded the results. 10 cents to calibrate vs $1 .for PH down i use a phosphoric acid based concrete cleaner available at HOMEDEPOT/LOWES. $12 will get enough to treat 100's of 1000's gallons .