waterboy

I am new to the forum so excuse me if this is one of those topics that has talked to death. I have a Hanna 9813-6 combination ph/tds/ec/temp meter. It is spot on as far as calibration goes. I use the gh flora 3 part series nutes. The problem is that when I measure the ppm on the veg mix 3-2-1, I read 1800ppm approx, the gh website says the actual ppm for that mix is near 750ppm?? The website does say that ppm meters using elect. current to measure ppm will be incorrect. What the hell does that really mean?? Does that mean on all liquid nutes the ppm on my meter, and just about all portable meters, will be incorrect?

How about tds/ec? Will they be affected also? Can anyone explain or point me in the right direction so that I can understand their relationship to ppm? Thanks Brothers
Peace

Viagrow

It is my understanding that most if not all "ppm" meters use some conversion standard of electro conductivity (EC) to measure. So essentially they are saying ALL meters will be wrong . . . but that conclusion seems odd.

Also, the calibration solution you used will have some effect. For instance, if you calibrate to 700ppm . . your readings well above that will be off. If you calibrate to 1400, you readings well below that will be off.

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waterboy

Thanks Viagro, I got turned on to this website: CannaStats - Nutrient Profiles for Cannabis
Great stuff, answered my question, plus a bunch that I didn't know enough to ask.
Peace Brothers