Quote:
Originally posted by scooby250
I just got a TDS meter for my aerospring system. Everything was going great i just wanted to have more control over nutrients. I was wondering what a good range for PPM is i heard somewhere between 300 and 400 is good, im at 363 right now. |
unfortunately your ppm TDS meter only measures conductivity, so all you really can ever know is the conductivity of the aqueous solution.
the conversion to ppm is usually 0.5 times the conductance EC measured in microsiemens/cm.
if you are reading 353 ppm on a meter that uses 0.5 then all the meter has done is measure 706uS/cm of conductance (distilled water with no other ions measures 0 conductance and 0 ppm)
if you started with distilled water and added nutes only then the EC of 0.706 would really be closer to 494 ppm of your nutrients in water (706 x 0.7)
but if you started with hard tap water with CaCO3 then that 0.706 EC is about 353 ppm 'cause the conductance is due to calcium carbonate ions
since this server times out longer posts we'll have to post multiple -since re-writing all the time is a pia